Resources

Daylily Dictionary

There are hundreds of words and phrases which have daylily-specific, or botanical explanations. This dictionary provides a living list of terms - most of which have been submitted by members and all have been reviewed by our Scientific Studies Committee. Terms found here are helpful in successfully growing, purchasing, exhibiting and enjoying daylilies. If you have a term for possible inclusion in the Dictionary, please submit it below.

Jump Ahead…

A|B|C|DEFGHIJKLMNOPQR |STUVWXYZ

or scroll through all terms below.

A Terms

Alkaloid

Any of numerous usually colorless, complex and bitter organic bases (such as morphine or codeine) containing nitrogen and usually oxygen that occur especially in seed producing plants.

Allele
  1. Either of a pair of alternative characteristics, such as smooth and wrinkled seed.
  2. One of a group of genes that occur alternatively at a given locus.

Most multicellular plants have diploid (two) sets of chromosomes. These chromosomes are referred to as homologous chromosomes. Diploid plants have one copy of each gene (and therefore one allele) on each chromosome. If both alleles are the same, they are homozygotes. If the alleles are different, they are heterozygotes.

Aneuploid

Having a chromosome count that is not an exact multiple of the haploid number, with either more or fewer than the normal number of chromosomes in the cell. Some daylilies converted with colchicine are suspected to be aneuploids.

Angiosperms

Flowering plants with seeds enclosed in an ovary. This differentiates them from gymnosperms with “naked” seeds like the conifers. Angiosperms, are the dominant group of plants on land, with around 230,000 described species. Daylilies are angiosperms. See also: monocots, dicots.

Anther

Each typical flower has six stamens attached at the base of the petals. Each stamen is comprised of two parts, a stalk (filament), and a two-lobed pollen sac called the anther. The pollen contains the sperm cells used to fertilize a daylily’s ova.

Anthesis

The period or state of being fully open, or expanded, of a flower; in full bloom. Also see: Diurnal, Nocturnal.

Aphids

Aphids are small, mostly less then one tenth of an inch, soft-bodied insects of the family Aphididae. The daylily aphid, Myzus hemerocallis, is, not surprisingly, often found on daylilies but there are many other kinds of aphids; some of which may also affect daylilies from time to time. The daylily aphid is light green in color and feeds in colonies between the leaves of the plant, inserting the mouth parts into plant tissue and sucking up the juices. Whitish specks are often noticed on the plants when aphids are present. These are the cast skins left behind after molting. (See lower image below.) They also excrete a sticky substance called “honeydew”. The image accompanying this text is of the related green peach aphid (Myzus persicae). The life cycle of aphids can be rather complex and can vary somewhat according to species and geographical region. In mild weather aphids can produce continuous generations rapidly by live birth without mating, most of the population being female. With the imminent onset of cold weather in Fall, males may be produced, mating occurs and the females lay overwintering eggs. In warm climates and in greenhouses, some species may omit the egg-laying stage and continue to reproduce by live birth through the winter, although where it is slightly colder they may hibernate as adults. Most aphids are wingless, but sometimes you will see winged forms. Natural enemies may keep populations down to levels where no treatment is necessary. Aphids are especially partial to plants fertilized with large amounts of nitrogen. If control is desired, insecticidal soap can be effective if the aphids are located where they can be directly hit by the spray. Numerous other low or non-toxic remedies are discussed in various references including repellent companion plants such as the allium (onion) family, coriander and anise.

Applique, Applique Throat

In a daylily bloom, an opaque color pattern originating in the throat and extending outward onto the midrib and tepal surfaces. The strong contrast and sharp distinct edges of an appliqued throat show no color bleeding into the surrounding petal tissue.

The term “applique” comes from the French word for “apply”,  and in art refers to one material applied to the surface of another.  Hybridizer Bill Munson used the term to describe throats in daylilies such as Hemerocallis ‘Chinese Temple Flower’ (Munson-I. 1980).  An appliqued throat has the appearance of being raised and applied or painted onto the surface color(s) of the tepals.  The applique can be variable over time and location.

The important distinction between appliques and normal extended throats is that there is no bleeding of color from the throat to the petal color and that there is a strong contrasting color separation, not soft blending.  Examples of extended throats that are not appliques can be seen in H. ‘Emerald Starburst’ (Doorakian 2004) and in ‘Kermit’s Scream’ (Norris-R. 2006)

Reference: Ted Petit, “The Patterned Daylily” The Daylily Journal, vol. 62, No. 2 (Summer 2007) pp. 125-141.

Chinese Temple FlowerH. ‘Chinese Temple Flower’ (Munson-I. 1980).  Used with permission from Sue Bergeron.

Catcher In the Eye
H. ‘Catcher in the Eye’ (Kinnebrew-J. 2001). Used with permission from Charmaine Rich

Spacecoast Sea Shells
H. ‘Spacecoast Sea Shells’ (Kinnebrew-J. 2003). Used with permission from Patricia Loveland.

Spacecoast Miss MargaretAn appliqued throat can occur on a daylily with no eye as in H. ‘Spacecoast Miss Margaret’ (Kinnebrew-J. 2008), Used with permission from Julie Covington.

Spacecoast Behavior Pattern…or, with an eye, as in H. ‘Spacecoast Behavior Pattern’ (Kinnebrew-J. 2006). Used with permission from Julie Covington.

Chinese Scribe…or with a watermark, as in H. ‘Chinese Scribe’ (Munson-R.W. 1991). Used with permission from Charmaine Rich.

Daylilies with extended throats that are not appliques are exemplified by:
KermitH. ‘Kermit’s Scream’ (Norris-R. 2006). Used with permission from Richard Norris, and…

Emerald StarburstH. ‘Emerald Starburst’ (Doorakian 2004). Used with permission from Gus Guzinski.

ARMILLARIA ROOT ROT, or SHOESTRING ROOT ROT

There are several different organisms that may be involved in rot diseases of daylilies, such as species of the fungi Fusarium, Phytophthora, Rhizoctonia, Pythium and Sclerotium as well as bacterial soft rot caused by Erwinia. In 2004, a fungus generally associated with woody plants was identified in diseased daylilies for the first time. Armillaria root rot infection is known most commonly as “Shoestring Root Rot” in North America because of the shoestring like structures it produces, and in some other countries it is referred to as “Honey Fungus” due to the color of the mushrooms.

The text below has been kindly written for us by Dr. Guido Schnabel of Clemson University, who made the initial identification of this disease in daylilies. This fungus is not likely to be a common cause of rot disease in daylilies but could be a possibility when gardens have been cleared from woodland, or where there are dead or diseased trees or shrubs known to be infected with Armillaria.

Root rot, Armillaria root rot:

A new fungal pathogen on daylilies. G. Schnabel, Department of Entomology, Soils, and Plant Sciences, Clemson University, Clemson SC 29634. schnabe@clemson.edu.

Armillaria root rot disease is a soil borne pathogen that primarily affects woody plants but occasionally is reported on herbaceous species. In June 2004, the disease was discovered for the first time on daylilies. The diseased plants were located in South Carolina and grown in well drained loamy soil that is supportive of Armillaria root rot disease. The site used to be woodland and was just recently cleared. Daylilies were planted around multiple hardwood stumps and an Armillaria root rot symptomatic dogwood tree.

Symptoms were similar to drought stress and included poor growth of the plant and yellowing of leaves. A cross section through the crown of wilting plants revealed necrotic areas with fan-shaped, white fungal mat growing inside. In some instances, mycelial fans were also discovered in primary roots. Black shoestring like rhizomorphs were found on and near the daylily and dogwood roots and in other places of the yard. These rhizomorphs are produced by the fungus to explore the area and look for new prey. They are initiated on a food base, such as tree stumps.

The causal organism of the Armillaria root rot disease in daylily was identified as Armillaria gallica H. Romagnesi & Marxmüller based on genetic fingerprinting. This species is most prevalent on the west coast and in the mid west of the United States but is also known to be a pathogen on trees on the east coast. It produces gill-bearing mushrooms typically in the fall at the base of infected trees and sometimes on shallow roots. The mushrooms grow in clusters, are brown, and possess an annulus (ring) around the stalk. Cultural or chemical control options have not been established for this new disease on daylilies but research is in progress.

Armillaria Root Rot on daylily.

Mycelial sheets in nectrotic tissue of a daylily crown.

Rhizomorphs intermixed with daylily roots.

Asexual Reproduction

Propagation by vegetative means, such as division or proliferation. All plants resulting from asexual reproduction are genetic clones of the original single plant from which they derived. Vegetative increase may be enhanced with BAP paste or BAP 10.

ASPARAGALES

The plant Order which includes the daylily family (Hemerocallidaceae) and many others such as the asparagus, onion, agave, lily-of-the-valley, iris, and hyacinth families. Black seeds are characteristic of most Asparagales due to a layer of phytomelan on the seedcoat (testa).

AXIL

The angle between a branch or leaf and the scape. Also see: Branch, Scape.

B Terms

BACK CROSS

A term used for breeding a plant back to either parent. See also: inbreeding

BAND or BANDED

A darker colored area just above the throat of a flower, on the petals only. If the band of color also appears on the sepals of the flowers, it is called an eye. Note in the 3 examples below, that the upper example shows a solid color band present only on the petals not the sepals and in the two lower examples that the color pattern within the band does NOT appear on the sepals on either of the two lower examples.

BAP

A type of paste used to produce greater vegetative reproduction, particularly proliferation, of a plant. Perhaps the best known is BAP IAA paste, the formula for which is: 3.0 grams anhydrous lanolin, 90 milligrams BAP (6-Benzylaminopurine), 90 milligrams IAA (Indole-3-acetic acid) and 160 milligrams (0.145 milliliters) DMSO (Dimethylsulfoxide).

BEARD or BEARDED

In botany, the term “beard” refers to a group of hairs, as in the bearded iris pictured below. It may also refer to an awn, e.g. the bristle-like projection from a grain such as barley. The terms “beard”, “bearded” and “awn” do not apply to daylilies, but are included here for reference.

BICOLOR

A daylily flower whose petal segments are of a completely different color than its sepal segments

BITONE

A flower with inner and outer segments of different tints of the same basic color. A bitone has lighter outer segments (sepals) and darker inner segments (petals). A REVERSE BITONE has the darker tones on its outer ring (sepals) and lighter coloration on the inner segments (petals)

BLACK, NEAR BLACK

There is no true “black” daylily because a gene for the color (black) is not known to exist is the genus Hemerocallis. “Black” or “near black” daylilies are either very dark reds or very dark purples.

BLEND

Flower with an intermingling of two or more colors.

BLOOM

That portion of the daylily that flowers. It begins as a bud on a scape, and proceeds to grow until it reaches maturity. At maturity, it opens its tepals to expose the flower’s form, color, distinctive markings (eye, halo, edging, midribs, throat) and the sexual portions consisting of the pistil and stamens. An individual bloom generally opens for a single day, then withers, only to be succeeded by one or more new blooms until all the buds on a scape have matured. The spent bloom may or may not produce a pod from which seeds are harvested.

BLOOM SCAR

The circular, usually white, marks left on the daylily scape after each spent bloom falls off. Each scar represents one bloom, so after the bloom season is completed, bloom scars can be counted (adding any seed pods) to determine the bud count for a cultivar.

BORDER

A distinctly different color found on the outer edges of the flower segments.

BRACT

A modified leaf found on a scape at an axil. The presence of a bract on the scape of a young plant may indicate that the plant has the potential for producing additional branching on new scapes in succeeding years. Also see: Axil, Scape, Branch.

BRANCHING

A stem that originates from the primary scape and bears two or more buds. Terminal branching occurs at the top of a scape and may be arranged to form a V (two branches) or a W (three branches – See Figure 3 below). Lateral (side) branches or “laterals” may occur along the scape where there are bracts. Neither a proliferation nor a stem with a single bud are included in the branch count. Branches may divide into sub-branches.

A branch count includes:
1. A terminal V is counted as 2 branches and a terminal W is counted as 3 branches. A scape that does not divide into a V or a W at its terminus is counted as 1 branch.
2. The number of lateral branches.
3. Sub-branches are not included in the count of branches.

Looking at the photograph provided in Figure 1, and noting the line drawing below it (Figure 2), you’ll find that each lateral stem bearing two or more buds is counted as a separate branch.

In Figures 1 and 2 at least two branches split into segments (sub-branches) along their length, with each segment containing several buds, however only stems which originate at the junction of the scape are counted as branches.

In Figure 1 (photograph above) and Figure 2 (diagram below), you will see a single bloom scar appearing on the scape itself. Since the scar indicates the presence of a single bloom, and by definition a branch must exhibit a minimum of two buds, a single bloom scar, even though it appears on a scape, does not count as a branch.

Count the branches which appear as stems having a junction with the bloom scape. Using the AHS definition of branching, and using the method for counting as described, the scape shown in Figures 1 and 2 exhibits six-way branching.

A scape terminal (the top) may be a single tip with several buds (one branch) ( Figure 3a); it may exhibit V branching (two branches) (Figure 3b); or it may exhibit a W (three branches) (see Figure 3c). Note that the scape shown in Figure 1 (above) exhibits a single terminal, without showing either V or W branching. This example should be counted as having a one-branch terminal.

BUD
  1. A young and undeveloped leaf, flower or shoot.
  2. Meristemic tissue enclosed by modified leaves; terminal and lateral buds.

BUD-BUILDING

Scientifically called “indeterminate inflorescence,” it means “continuing to grow at the apex” or end of the scape. A pattern of growth on scapes in which buds continue to form as lower buds open. A scape showing this characteristic will get taller through the bloom season. It is a somewhat unreliable trait, dependent upon weather and growing conditions. Later bloom tends to be sparse.

BUD COUNT

Since each daylily flower is only open one day, the number of buds each scape carries is indicative of how many flowers the plant will bear on a single scape. The bud count can be determined by counting the number of buds, seed pods and bloom scars and adding these together.

BULB MITES (Rhizoglyphus spp)

Have been found in several countries including the USA, Canada and Europe. These are very small shiny whitish mites with reddish brown legs, sometimes having two brown spots on the back. Bulb mites feed in colonies in rotting tissue, usually at or below ground level, and are found on many different plants. You may see groups of tiny white specks some of which, if you watch very carefully, may be observed to be moving slowly. A magnifying lens is necessary for more detailed inspection. While they are often secondary to some other damage to the plant such as mechanical injury, insects etc., these mites are also thought capable of attacking healthy tissue and can introduce diseases with the pathogens they carry. Bulb mites can survive in the absence of a growing plant by feeding on other organic matter. If plants are growing poorly, send a sample to your Extension Diagnostic Service, or your country’s equivalent, for investigation and advice.

BULBS

NOT a generally accepted daylily term. Daylilies are herbaceous perennials and do not grow from bulbs like true lilies (lilium), tulips or narcissus. A frequent question asked by newcomers to daylilies is “…so, are they bulbs or what?” Also see: Stem.

C Terms

CAPSULE

Dry fruit (matured ovary) composed of two or more carpels that split open at maturity to release the seeds from the locules (chambers); commonly called a seed pod. Typically a daylily capsule has 3 locules. See also: ovary, carpel, seed, locule, pod.

CARPEL

The female floral organ that bears ovules, which develop into seeds if fertilized; it can be a simple pistil or one unit of the compound pistil as in a daylily. See also: ovule, seed, pistil.

CASCADE, CURLING

One of three defining forms of an Unusual Form daylily. A “cascade” refers to a small, steep waterfall or something resembling it. The cascade form may include cascading or curling of segments. Also see Cascading, Curling, Segment, Unusual form.

Quilling - Asterisk

CHELATED COMPOUND

A plant with two genetically different tissues growing side by side. Chimeras may or may not be stable. Ploidy chimeras are common in plants treated with colchicine, part of the tissues being converted to tetraploidy, other parts remaining diploid. Also see: Colchicine, Diploid, Tetraploid.

CHLOROSIS

Chlorosis is a yellowing of leaves resulting from a reduction in the amount of chlorophyll, the green pigment necessary for photosynthesis. The yellow color may cover the entire leaf, or be restricted to certain areas with parts of the leaf still green. When only the spaces between the leaf veins become pale but the veins themselves remain a normal green, this is referred to as an interveinal chlorosis. Chlorosis is usually a symptom that something is wrong; however, a few of the oldest leaves becoming yellow may merely be a normal aging process. Both the pattern of the yellowing on the individual leaves, and the distribution of affected leaves on the plant, e.g. the whole plant, youngest leaves, oldest leaves are often used to aid in diagnosis. Some possible causes are incorrect soil pH, nutrient imbalance, unsuitable soil moisture levels, root problems, overfertilization, disease, insects, and herbicide injury. The image below illustrates a chlorotic daylily growing adjacent to a normal green one. In this particular instance the yellowing is interveinal as opposed to covering the entire leaf.

chlorosis

CHROMOSOME
  1. The self-replicating genetic structures of cells containing the cellular DNA.
  2. One of a definite number of minute bodies in the cell nucleus of all plants and animals through which characteristics are inherited.

Daylily chromosomes come in sets of eleven. Cells of diploid daylilies contain 22 chromosomes (two sets). Triploids contain 33 (three sets), and tetraploids contain 44 (four sets). Because the chromosomes in a nucleus must divide in half to form ova and pollen, triploids, with an odd number of chromosomes, are usually sterile. Tetraploids have not been found in species daylilies.

CLONE

A genetically uniform assemblage of individuals, derived originally from a single individual by vegetative propagation, e.g., in daylilies by natural division of ramets, by rooting proliferations, by crown cuttings, tissue culture, etc. Also see: Crown, Cultivar, Proliferation, Ramet.

CLUMP

Three or more fans of a cultivar grouped together. Also see: Cultivar, Fans

clump

CMO (Cold Morning Opener)

An informal term indicating that a daylily opens completely even when temperatures are low. The actual temperature that determines a CMO is not defined; having a series of cool temperature nights is also a factor. CMO is more of a concern in temperate regions.

COLCHICINE: C22H25NO6

A poisonous alkaloid extracted from the corms or seeds of the meadow saffron or autumn crocus (Colchicum autumnale) and used on mitotic cells to induce polyploidy by dissolving the spindle fibers during cell division. Also see: Alkaloid, Mitosis, Polyploidy.

COMPLETE-SELF

A flower having perianth segments, throat, pistil and stamens all the same color. Also see: Perianth, Pistil, Segment, Self, Stamen.

CONVERSION
  1. A plant that was originally diploid in its chromosome makeup, but which was chemically treated with colchicine and altered to tetraploid. Conversions may or may not be stable. Conversions are distinguished by the prefix “Tet” or “Tetraploid” as in TET BARBARA MITCHELL. The hybridizer and the converter are both identified. The hybridizer’s name is listed first, followed by a slash and the name of the person who performed the conversion. In the example of TET. BARBARA MITCHELL, Pierce/Stamile. Also see: Chimera
  2. What happens to a lawn when a daylily gardener moves in.
  3. What happens to a mixed perennial bed when a gardener discovers daylilies.
COTYLEDON

The leafy portion of a plant’s embryo. The embryo is the part of the seed from which a mature plant develops. It consists of a short root, the radicle, and a short bud, a plumule, connected by a short shoot, the hypocotyl, that bears one or more cotyledons. Because they form within the seeds, cotyledons are known also as seed leaves. Flowering plants, called angiosperms, have embryos within their seeds that form one or two cotyledons, also often referred to as “seed leaves”. Those with one cotyledon are known as monocotyledons or monocots. Monocots include daylilies, orchids, palms, bananas, pineapples, and corn. Most have leaves with parallel veins and flower parts in multiples of three. Angiosperms with two cotyledons are called dicotyledons or dicots. They produce leaves with a netlike pattern of veins and flower parts in multiples of four or five. Apples, cherries, beans, squashes, and tomatoes are common dicots.

When seeds germinate, the cotyledon/s may remain below the soil surface (known as “hypogeous” germination), or emerge above it (known as “epigeous” germination), depending on the type of plant. For example, germinating daylily seeds show hypogeous germination, the single cotyledon remaining enclosed within the seed coat below ground. An example of epigeous germination would be a bean seed, where its two cotyledons are raised above ground before the true leaves develop.”

dicot seedling

Dicot Seedling

monocot seedling

Monocot Seedling

CRISPATE

One of three definitions of an Unusual Form daylily. Crispates may contain pinched segments, twisting segments, or quilling on one or more segments. Also see: Quilling, Segment, Twisting, Unusual Form.

pinched crispatepinched crispate

CRISTATE

A form of sculpting that refers to appendages of extra petal tissue growing from the midrib or elsewhere on the surface of the petals. When the extra tissue grows from the midribs, the form is called Midrib Cristate.

crested

CROSS-POLLINATION

The process of placing the pollen from the anthers of one cultivar on the stigma of another. Also see:The process of placing the pollen from the anthers of one cultivar on the stigma of another. Also see: Anther, Cultivar, Pollen, Stigma.

CROWN

The small white core located between leaves and roots, that is the modified stem of the daylily plant. Some crown tissue must be present for any daylily division to be viable.

crown

CROWN AND ROOT ROTS

Disease causing organisms (pathogens) and environmental conditions all play a role in crown and root rots of plants. Daylilies are susceptible to fungal rots caused by organisms such as Fusarium, Phytophthora, Sclerotium, Rhizoctonia and Pythium, as well as bacterial soft rot involving Erwinia. Very recently (2004) daylilies have been discovered susceptible to Armillaria, or shoestring root rot. Symptoms of rotting can include poor growth, wilting, yellowing of leaves, obviously mushy tissue and death of the plant. Bacterial soft rot is well known for its particularly foul smell.

Overwatering, overfertililization and other poor soil conditions and plant stresses favour rot diseases. While fungal pathogens can invade intact plant tissue, bacteria can only infect through existing openings such as an injury from garden tools, pests, other diseases, frost damage etc.

In gardens where daylily rot is frequent, assistance in diagnosing the cause can be obtained by submitting a diseased plant to a diagnostic laboratory. Contact your local Master Gardeners or Extension Office for information on where to send a specimen.

CUCUMBER BEETLES

Cucumber beetles come attired in either stripes or spots and both are native to North America. Both dress variations have been reported on daylilies. There are eastern and western versions of both the Spotted Cucumber Beetle, Diabrotica spp. and the Striped Cucumber Beetle, Acalymma spp.; the eastern Spotted Cucumber Beetle is also known as the Southern Corn Rootworm. The adult beetles are roughly a quarter inch in length, the spotted version having 11 black spots (or twelve if you count one large merged one as two); three black stripes adorning the striped cucumber beetle. The wormlike larvae of both beetles feed on several different plants below soil level (but only cucumber and squash family plants in the case of the striped cucumber beetle). The adult beetles chew on foliage and blooms of a range of ornamental plants and vegetables. There is one generation per year in the north, up to three or four in the south. Most suggested non-toxic controls are not appropriate for ornamental plantings, e.g. floating row covers, deep straw mulches, interplanting with radishes, etc.

SpottedStriped

CULTIVAR

A combined word for “cultivated variety.” Denotes an assemblage of cultivated individuals that, when reproduced sexually or asexually, retains its distinguishing features. Nearly all registered daylily cultivars are propagated vegetatively and retain their identity as clones. Also see: Clone, Variety.

CUTWORMS

There are a number of different species of cutworms occurring worldwide. They feed at night and are often seen when cultivating around plants, curled up just under the soil surface during the day as in the image of the Variegated Cutworm, Peridroma saucia. Cutworms are caterpillars; the larvae of nocturnal moths, and measure around one to two inches in length. Some chew into the base of the plant close to the soil surface, often causing the plant to topple over; others climb up the plant to feed. Depending on the species, there may be one or more generations each year. Where they are suspected of having caused damage, carefully investigating the top inch or so of soil adjacent to the plant should reveal the culprit, which can then be removed. Other possibilities are biological controls such as Bacillus thuringiensis (BT – said to be most effective against cutworms when mixed with a bait of moist bran and molasses) or beneficial nematodes. Small plants can have “collars” made from various items placed around their bases and pushed partly into the soil surface. Materials such as wood ashes, crushed egg shells or diatomaceous earth may be worth a try, sprinkled around the base of the plants.

cutworm

CYTOLOGY

A branch of biology dealing with the structure, function, multiplication, pathology and life history of cells.

CYTOPLASM

The protoplasm of a cell external to the nuclear membrane.

cytoplasm

D Terms

DAYLILY

Plants of the genus Hemerocallis, family Hemerocallidaceae. Some older references may still include Hemerocallis in the lily family, Liliaceae.

Generally, a single daylily bud is in bloom for a single day before it begins to wither. Multiple buds on the scapes provide bloom over a number of weeks each bloom season.

Ancient Chinese used the plant’s roots, leaves and flowers for food. They also used its roots and crown as a pain reliever, a diuretic and for other medicinal purposes.

Its botanical name, Hemerocallis, derives from two Greek words meaning “beauty” and “day,” referring to the fact that each flower lasts only one day.

In some dictionaries and other reference works, this plant may be referred to as “day lily,” but the spelling was consolidated into a single word in 1923 upon the recommendation of the American Joint Committee on Horticultural Nomenclature, as reported by the publication Standardized Plant Names, 1923 edition, Preface, p. x and p. 199.

DAYLILY RUST

A fungal pathogen that attacks daylilies.

Daylily rust is caused by the fungus Puccinia hemerocallidis and affects the leaves and scapes. It is not a new disease of daylilies, having been reported previously in China, Taiwan, Korea, Japan and Russia (Sakhalin, Kuriles and Siberia*). Unfortunately, the disease has now arrived in North America, and was first identified in the southeastern United States in August 2000. In nature, the main method of rust spread is by wind borne spores.

rust images

Infected Daylily Plant

rust images

Close up of pustules on leaf

Reports from AHS members indicate that in North America daylily rust has successfully overwintered in USDA Hardiness Zone 7 and milder. At the current stage of our knowledge, it is safest to assume that if any daylily foliage remains green through the winter in an already infected garden, there is a possibility the rust could survive inside those leaves. In very mild winter climates the familiar yellow-orange powdery “summer spores” (urediospores) produced from the spots (pustules) on daylily leaves may cause repeated infection cycles year round. A spore is similar to a plant seed, and like a seed requires moisture and appropriate temperatures in order to germinate. It is not yet known how long daylily rust urediospores can remain alive on leaves until conditions become suitable for germination and infection, or exactly how far they can travel on the wind to new daylily leaves. Rust spores can often travel many miles on air currents.
Rust diseases may also survive winter as mycelium (the strands which form the body of the fungus inside the leaf) but this can only take place where some infected leaves remain alive through the winter such as in milder climates, or where there is protection from greenhouses, deep snow cover, heavy winter mulch, or proximity of infected plants to the warming walls of a house, for example.

Another means by which rusts can overwinter is in the form of “winter spores” (teliospores). These are dark colored spores which most commonly appear at the end of the growing season in response to shorter days and cooler temperatures. The spots and streaks containing teliospores on a daylily leaf are blackish, in contrast to the more familiar orange pustules of urediospores. “Winter spores” are hardier and more durable than the “summer spores” and lie dormant on dead daylily leaves over winter. In the spring they germinate to produce another type of spore but this cannot infect daylilies. Instead, these new spores must be transported by the wind or other means to a plant of the alternate host, Patrinia, which is a perennial plant also of Asian origin. After completing the next stage of the life cycle on a Patrinia plant, the rust can then pass back to daylilies. Thus it is possible that in climates where the rust cannot survive the winter as mycelium or urediospores, it may still be able to continue the infection in the subsequent year if there is a plant of Patrinia in the vicinity.

Patrinia is not common at the moment in North America, but several species are being offered for sale both as plants and seeds. Not only does it pose a threat to daylilies as far as overwintering of the rust is concerned, but the rust life cycle stage on Patrinia is a form of sexual reproduction which may increase the chances of daylily rust becoming able to infect currently resistant daylily cultivars. However to date we are not aware of any patrinia plants having been infected with daylily rust in North America. At one time, Hosta was also thought to be susceptible to daylily rust, but further research has shown this is not the case.

When acquiring new daylilies, whether by trade or purchase, it should be born in mind that these plants could be carrying a rust infection even though it isn’t necessarily visible at the time of receipt. There have been numerous reports of rust first becoming apparent several weeks or months after the plants have arrived. The fungus may be alive inside a leaf, or spores be hiding on a leaf, without showing any obvious signs externally. An early infection may go undetected until the rust begins to form more spores, at which time it produces the characteristic yellow-orange pustules. From this point on, the infection may soon spread throughout one’s garden or nursery. It is advised as a precaution to isolate all new daylilies well away from existing daylily plantings for several months or a growing season to minimize rust spread if they turn out to be infected.

On receipt of new daylilies, some growers are peeling the outer layers of leaves from new plants right to the crown, and then cutting the remainder about one to two inches above the crown. The plant may then be soaked in fungicide if desired. This procedure may add to the transplant and shipping shock of the divisions, and that risk should be weighed against the desire to protect one’s garden and neighborhood from possible rust infection. Although there is no guarantee this treatment will prevent rust on new plants which have been exposed to the disease, it should significantly reduce the risk. Fungicide or disinfectant treatment prior to shipping does not guarantee a rust-free plant, and overseas purchasers should not assume a phytosanitary certificate indicates a clean plant.

Check new plants daily for rust especially the undersides of the leaves. Some gardeners report missing the rust because it was not visible when looking down onto the top surface of the leaves. Early signs of rust, prior to pustule development, are leaf spots which could be mistaken for some other disorder. Rust pustules are raised, and this can easily be seen with a small magnifying glass. A few other substances on leaves may appear raised, such as other plant seeds, pollen, and even fertilizer or pesticide residues. Yellow-orange powder (large numbers of spores) comes off on a white tissue when a rust infected leaf is wiped.

Differences in rainfall, humidity, temperatures and cultural practices will cause the severity of the disease to vary between gardens. Because fungicide availability and labeling differs regionally it is best to contact your local Extension Service or Ministry of Agriculture for the most recent advice on treating daylily rust. Trial results from Drs. Buck and Williams-Woodward at the University of Georgia were published in the Spring 2002 issue of the AHS Daylily Journal. The summary indicated that “daylily rust can be controlled under greenhouse conditions by fungicide applications, in particular, mancozeb, chlorothalonil, azoxystrobin and triadimefon.” Products should be rotated to reduce the risk of fungicide resistance developing. Alternate between a systemic fungicide and a contact or protectant fungicide. Application may need to be repeated as often as every seven to fourteen days – follow product label instructions. It is often recommended to remove the foliage from all plants discovered to have rust at the first sign of infection, cutting just above the soil level. Similarly cut all apparently healthy plants in the vicinity. However, if the infection continues after this initial cutting back, it is not recommended to continue repeatedly removing all the foliage. For those who do not wish to use fungicides treatment may be limited to continuous removal of individual infected leaves as they are noticed. Removed leaves should be destroyed, preferably by burning or burying where this is possible. Spores can remain alive for a while even on a dead leaf and spread from there on the wind. Opinions differ regarding the safety of composting infected leaves. Some people are spraying the plants with a fungicide before cutting the leaves in order to reduce spore numbers around the remaining stubs of plants, and then spraying again afterwards. Fungicide applications will not be as effective if the foliage is not removed from the plants. Because leaf moisture for several hours promotes rust spore germination, overhead watering should be avoided wherever possible. If it cannot be avoided (by use of soaker hoses etc. which keep the foliage dry) then timing should be such that the leaves remain wet for the shortest possible time – i.e. do not overhead irrigate late in the day or in the evening. Also, plant spacing should be sufficient that leaves dry quickly following rain or irrigation.

While daylily rust may kill the foliage on some cultivars, it is unlikely in the short term to actually kill the infected plant. However, it is not yet known what the effects of continuous infection will be on individual daylilies. It is possible that some may become weakened and thus susceptible to other stresses and diseases, or that bloom could be reduced. Looking into the future, steps are already being taken by some hybridizers to monitor plants for rust susceptibility in the hopes that it will be possible to breed rust resistant cultivars. Unfortunately, many Hemerocallis species are reported to be susceptible to the rust in its native habitat, so whether any of these will be useful in the development of new cultivars is not yet known.

Other leaf problems may resemble daylily rust. To identify daylily rust, leaf streak, spring sickness and other non-rust disorders that affect Hemerocallis, see the following web site hosted by AHS member Susan Bergeron: http://www.ncf.ca/~ah748/rust.html

The above site also contains much more detailed information on the life cycle (including images of the rust on the alternate host, Patrinia), fungicide information, a list of reported host species, images of the leaf peeling process for new plants, contact information for local assistance, notes from presentations by plant pathologists about daylily rust and much more which is beyond the scope of this definition. The AHS provides this link as a source of information. The AHS does not have any control of the content on the site.

We do not have all the answers about this fungus yet, but we will try to keep this page updated as new developments arise that may change growing methods, prevention methods and practices related to rust.

*Hiratsuka, N., Sato, T., Katsuya, K., Kakishima, M., Hiratsuka, Y., Kaneko, S., Ono, Y., Sato, S., Harada, Y., Hiratsuka, T., and Nakayama, K. 1992. The Rust Flora of Japan. Tsukuba Shuppankai, Ibaraki, Japan. Pages 710-711.

DECIDUOUS

The term deciduous refers to daylilies that lose their foliage completely before or shortly after frost and over-winter with pointed foliage buds, usually just beneath the soil surface. Deciduous plants will resume growth in spring. Also see: Dormant, Foliage Habit.

DEHISCE

The process of splitting open a ripened seed pod and expelling the seed. As the seed pod continues to dry out, the pod will further split and drop the seeds to the ground where a new generation of plants may emerge.

dehisce

DIAMOND RUST

Flowers having structures that produce a glitter-like quality on the petal surface. When the sparkles appear white, it is referred to as diamond dusting. Some reference works also recognize the fact that some of these reflections on yellow cultivars appear to be gold and yellow – these are called gold dusted.

diamond dustinggold dusting

DICOTYLEDONS, DICOTS

One of the two major types of flowering plants, or angiosperms. The dicotyledons are so named because sprouting seeds have two primary leaves or cotyledons. Other common features of the dicots are leaves with branching or net veining and flowers with four or five tepals or multiples of these. Daylilies are NOT dicots. See also: monotyledons.

Examples of dicotyledons would be roses, most fruit trees such as apples, pears, cherries and peaches. (5 petals)

dicots

DIPLOID (DIP)

A plant having two complete sets of the basic set of chromosomes. A diploid daylily has 22 chromosomes. One set of 11 comes from the egg cell, one set from the sperm cell in the pollen.

DISEASES

While daylilies have a reputation as being disease free, there are some plant diseases that affect daylilies, most notably, Daylily Rust has been a cause for recent concern.

Other diseases that affect daylilies include: Spring Sickness, Leaf Streak, Crown Rot and now, most recently (September 2004), Shoestring Root Rot also known as Armillaria and in 2005, the first infection found of the Tobacco Ringspot Virus in a daylily.

DISSEMINATED

As applied to Hemerocallis, the term simply means that divisions or proliferations of a particular plant (clone) have been distributed and are being grown in gardens other than the one in which it originated. UNDISSEMINATED refers to a plant whose divisions and proliferations are found in only one garden.

DIURNAL

A daylily flower that opens in early morning or during the day.

DIVISION
  1. Refers to an individual unit in a clump, each portion of which is identical to the parent plant. Also see: FanRamet.
  2. The process of breaking a multifan clump of daylilies into several individual plants. Each plant can be termed a division.

Division

DOMINANT

Mendel (not otherwise identified) “… those characters which are transmitted entire, or almost unchanged in the hybridization, and therefore in themselves constitute the characters of the hybrid, are termed the dominant, and those which become latent in the process recessive. The expression ‘recessive’ has been chosen because the characters thereby designated withdraw or entirely disappear in the hybrids, but nevertheless reappear unchanged in their progeny …”

DORMANT

Dormancy is a temporary suspension of visible growth of any plant structure containing a meristem*.  The term “dormant” is not restricted to deciduous plants but applies also to evergreen and semi-evergreen plants, which can retain some, or all, of their foliage while having dormant buds. All daylilies, regardless of foliage habit, are capable of cold temperature dormancy in the technical sense where it gets cold enough to suspend growth.

DOUBLE

Single flowers consist of two whorls (layers) of perianth segments: the sepals and the petals. A double flower has more than one petal whorl (hose-in-hose double), or a stamen whorl that contains petaloid (petal-like) stamens (peony type double). In the peony type, carpels may also be petaloid. Individual flowers may be a combination of both double types.

Outgrowths of extra tissue from the midrib or elsewhere on a petal are not considered to constitute a double. Extra segments in the normal two perianth whorls classify a flower as polymerous rather than double.

See also: floral whorl, hose-in-hose double, peony type double, petaloid, stamens, carpel, polymerous.

hose in hose doublePeony Type Double

DUSTING

Used in two ways:

  1. to describe texture for “a flower with a velvet-like wash,” or…
  2. in reference to color for “a flower with a wash of another color over the basic color.”

Also see: Overlay, Wash. All three terms are somewhat interchangeable.

DWARF

Daylily with scapes up to 12 inches tall and may bear miniature, small, or larger flowers.

E Terms

EDGED

Distinctly different color occurring along the outer edge of the segments of a daylily.

Edged

EDGES

Edges refer to the outer periphery of the petals and occasionally the sepals.

  1. Edges can be structural, i.e. have knobs, braids, tentacles, fringe, and teeth.
  2. Edges can also be of a different color. If the edge is narrow and gold, silver, or white, it is referred to as a wire edge.
  3. Edges of a different color or colors can be narrow (referred to as a picotee) or wide (referred to as a border).
  4. Some structural edges reach down into the surface of the flower. These super sculpted edges give a three-dimensional quality to the flower.

edgesedgesedgesedges

EMO (Early Morning Opener)

EMO (Early Morning Opener): an informal term used by daylily growers to indicate a cultivar with flowers that fully open early in the morning. This trait is particularly desired by daylily growers who work during the day and wish to view their daylilies before leaving for work. Some nocturnal daylilies can be mistaken for EMO’s but their flowers actually open the evening before and are open all night.

EUROPEAN EARWIG

EUROPEAN EARWIG – is not a native insect, but introduced to North America and first discovered in Rhode Island in the early 1900’s. There are also native earwigs, but they are considered mostly beneficial. The European Earwig, Forficula auricularia, is about three quarters of an inch long and has pincers at the rear. They feed mostly at night, and are often especially abundant near outdoor lighting. Their life cycle is particularly interesting in that the mother actually tends the young until they are old enough to fend for themselves. There may be one or two generations a year. The young earwigs damage many different plants mostly by eating holes in leaves. Adults feed on flowers and fruit, and can often be seen in daylily blooms early in the morning. Where an earwig or two can be seen in a daylily bloom, there will frequently be many more hiding in the bases of fans between the leaves where their droppings make a considerable mess. Insecticidal soap is effective if you can score a direct hit.

earwig

EVERGREEN

The foliage habit of daylilies that retain their foliage throughout the year. In cold winter climates, evergreen daylilies over-winter as a mound of frozen pale green foliage. Evergreens may resume growth during a mid-winter thaw in mild climates. Evergreen daylilies do not set resting buds.

EXHIBITION

A show where daylilies are displayed and often judged. Most exhibitions are open to the public (free admission) after the judging has taken place. The flowers can be displayed on cut scapes (stems), or the individual blooms can be displayed ‘off scape’ in separate divisions. In ‘official’ AHS sanctioned shows there are well defined show sections based on flower size and flower forms and whether those scapes being displayed are of registered cultivars or seedlings (not yet registered daylily plants). In AHS exhibitions, judging is done by certified AHS Exhibition Judges. Exhibitions are generally sponsored by local daylily clubs.

Show Scapes

Image above of a show table after judging.

EXOTIC

“Exotic” is a botanical and horticultural term that refers to plants that are “…foreign, alien, belonging to another, not related, incongruous, different from…” (from Stearn’s Botanical Latin Fourth Edition [1992, paperback version 2004, reprinted 2008], Timber Press.)

“Exotic species:  An introduced, non-native species” (from Oxford Concise Dictionary of Botany 1992, Oxford University Press)

“exotic: Of foreign origin or character; introduced from a foreign country or a different region.  An exotic plant is one not native to the place where it is growing, such as Japanese honeysuckle, which has naturalized in the northeastern states, or eucalyptus trees, which have naturalized on the west coast.” (from National Gardening Association Dictionary of Horticulture, copyright 1994, published in Penguin Books 1996.)

The plants of the genus Hemerocallis may be referred to as exotic in North America, but not in Asia where they are native. (This term could also apply to the daylily leafminer, daylily gall midge, and daylily rust, since the term is also used for introduced pests.)

EXTENDED FLOWERING / BLOOMING

In daylilies, flowers that remain open 16 hours or more.

EXTRA LARGE DIAMETER

A daylily cultivar which has been registered with a bloom size of 7 inches or greater but which is not registered in a specific form category (double, spider, unusual form, polymerous, sculpted) by the hybridizer.

For Exhibitions (accredited daylily shows) extra large diameter flowers are classified by bloom size in Division I, Registered Extra Large Flowers.

For AHS Awards, the “Extra Large Diameter Award” is designated for cultivars that are registered with blooms measuring 7” or greater that are not also registered as spiders or Unusual forms.

EYE, EYE ZONE

A darker colored zone on the petals and sepals of the flower just above the throat. Notice that in the examples below the eye color also appears on the sepals. If the dark color only appears on the petals, it as called a band.

Eye

F Terms

FAMILY

A group of plants in related genera, all of which share characteristics not found in other families.

FAN

Terms FAN, DIVISION, and RAMET are interchangeable. Each refers to an individual unit of a clump, containing leaves, crown, and roots. Within a clump, each fan is genetically identical to the parent. Also see: DivisionRamet.

Fan

FASCIATION, FASCIATED SCAPE

Abnormal development from a single growing point (meristem), most commonly resulting in a flattened, wider than normal stem (scape), often with more than the expected number of flowers. In appearance, fasciation may give the impression of multiple fused stems.

There are several proposed causes, including mechanical injury and pests or diseases, along with environmental factors. A plant that produces a fasciated stem will not usually do so again in the following growing season.

fasciation

FEATHERED

A pattern in the eye zone of a daylily that exhibits a feathered/feathery appearance.

FERTILE

Capable of producing viable ovum, pollen, or both. A plant which can contribute genetic material for the creation of viable seeds.

Fertility does not affect a daylily’s garden value, but it does become a serious consideration when a grower intends to hybridize with

FFO

Date of the “first flower open” or first flower to bloom, of a given cultivar. These furnish coarse bloom sequence and bloom period indicators in a specific locality.

FILAMENT

Part of a stamen. Stalk-like structure attached to the base of a daylily’s petals. At the end is the two-lobed anther containing the pollen. Also see: AntherPollenStamen.

filament

FLORAL WHORL

One of the layers of modified leaves that make a flower; a complete flower has four whorls: sepals, petals, stamens, and pistil(s) from base to top. See also: sepal, petal, stamens, pistil.

Whorls

Daylily flower with some petals and sepals removed to show the four floral whorls. Frontal view below.

Whorls

FLOWER
  1. That part of a higher plant that is modified for reproduction and consists of a shortened axis bearing modified leaves.
  2. A plant cultivated for its blossoms.
FLOWER FORMS

The shape or structure of a daylily flower. The AHS officially recognizes the following forms for registration and exhibition purposes: single, double, spider, unusual form, and polymerous flowers.

(In registering a daylily all form characteristics of the flower should be considered and there is additional information, such as sculpting, that should be provided in registering a daylily that may, or may not be taken into consideration when showing a flower.)

Single — Daylily flowers that have three petals, three sepals, six stamens and one pistil(comprised of three carpels) are known as “single” daylilies. A single daylily flower may occasionally have fewer or more (see “polymerous”) parts per whorl. Also see “monocot”, “double”.

perianth segments

Double — Double daylilies, like single daylilies, come in different forms. ‘Hose-in-Hose’ doubles have extra whorls (layers) of petals so that there appears to be a flower within a flower. ‘Peony type’ doubles have petaloid (petal-like) stamens inside the normal petal whorl. Carpels may also be petaloid.

peony double

Spider — A flower whose petals have a length-to-width ratio of at least 4 to 1 (i.e., 4:1). Length is measured with the segment fully extended. Width measurement is taken as the flower grows naturally. (Older literature may designate “Spiders” as having a ratio of 5:1, and “Spider Variants” as having a ratio of 4:1. AHS merged the two classes into the one spider class in 2003.)

spider

Unusual Form — A class of daylilies based exclusively on the shapes of the petals or sepals. These shapes include Crispate (pinched, twisted, or quilled), Cascade, and Spatulate. One or more of these shapes must be displayed on at least 3 petals or 3 sepals.

Pinching – Floral segments with sharp folds giving a pinched or folded effect.

pinched

Twisting – Floral segments which present a corkscrew or pinwheel effect.

twisting

Quilling – Floral segments turn upon themselves along their length to form a tubular shape.

quilling

Cascading/Curling – Narrow floral segments with pronounced curling or cascading, which revolve upon themselves in the manner of a wood shaving.

curling

Spatulate Floral segments markedly wider at the end like a kitchen spatula.

spatulate

Polymerous — Polymerous is an adjective used to designate a daylily with more than the normal number of segments in each floral whorl, i.e., more than the normal three sepals (usually four or five) in the outer whorl and more than three petals (usually the same number as sepals) in the inner whorl.

polypoly

Examples: left, a 4×4 polymerous bloom, on right, the rarer 5×5 polymerous bloom.

Multiform: This term is used where the daylily in question has been registered correctly as exhibiting 2 or more of the forms spider, unusual form, polymerous, or double.” An example of a multiform is a daylily that is both a spider and an unusual form, or a polymerous double, etc, but a single spider, etc. is not a multi-form.

1

Trickster (Tankesley-Clarke, 2004) UFo Crispate-Cascade & Double 98%

2

Firefly Frenzy (Joiner-J. 2002) UFo Crispate & Double 98%

3

Sebastian The Crab,(Joiner-J. 2003) registered as a Double & an Unusual Form.

4

Osterized (Hite-Davisson, 1999) is registered as a polymerous UF

Sculpted: A term used to describe three-dimensional structural features involving or emanating from the throat, midrib or elsewhere on the petal surfaces. Sculpted forms belong to one of three different groups: Pleated, Cristate and Relief.

These form characteristics are collected on the current registration form but are not currently recognized for exhibition purposes.

Other Descriptive Terms (Sub-forms):

Other terms used to describe flower shapes, such as “circular”, “flat”, “informal” “recurved”, “star”, “triangular”, and “trumpet” are called “sub-forms”. (See Judging Daylilies, pp. 37-

Circular: When viewed from the front of a bloom, the flower appears round. Segments tend to be short, wide and stubby, and generally overlap, giving a full appearance.
round

Flat: When viewed from the side of a bloom, flowers are perfectly flat except for the concave throat.

flat

Informal: When viewed from front of bloom, flower segments have no definable shape. Segment placement may be irregular, widely spaced or floppy.

Recurved: When viewed from the side of a bloom, flower segments flare, but the ends of some segments roll back or tuck under. When the sepals are all recurved, and the petals are not, the result is a triangular form, when both sepals and petals recurve, the result is often the round form.

recurved

Star: When viewed from front of bloom, flower segments tend to be long and pointed. There is space between the segments, and the shape looks like a three-pointed or six pointed star.

star

Triangular: When viewed from the front of the bloom, the flower segments form a triangle. The sepals generally recurve.

triangular

Trumpet — When viewed from side of bloom, flower form resembles a true lily. Segments rise from throat in an upward fashion with little flare.trumpet

FOLIAGE
  1. The combined mass of leaves of a plant.
  2. The portion of a daylily above the crown, excluding bloom scapes, which consists of individual alternating leaves grouped into fans.
  3. The leaves of a plant whose primary job is to produce food through photosynthesis.
FOLIAGE HABIT

This term refers to the winter behavior of daylily leaves. Daylilies are either deciduous, semi-evergreen or evergreen. This indicates how the cultivar’s foliage passes winters in the hybridizer’s garden, but is not necessarily an indication of how it will behave elsewhere under differing environmental conditions. Note that hardiness and foliage habit are inherited separately, thus not all evergreens are tender and not all deciduous plants are hardy.

FRAGRANT

This term refers to the amount of scent a flower may exhibit.

Daylilies have a very light, pleasing scent. Some cultivars are more heavily scented than others. Scent may vary with the time of the day and weather conditions.

The AHS awarded the L. Ernest Plouf Award each year for the best dormant and fragrant cultivar as voted by the AHS Garden Judges during the years 1979-2003.

FULVOUS

Reddish-yellow “tawny” color of H. fulva and related daylilies.

fulvous

FUNGUS GNATS

Are one of those pests where the life stage that you see is not the one doing the damage. They are mostly noticed on indoor plants and seedlings, although they do also occur outdoors in the garden. Fungus gnats belong to the family Sciaridae and the adults resemble small mosquitoes about one eighth of an inch in length. They are not strong fliers and can sometimes be seen taking a break on the soil surface. They are attracted to moist growing media with high organic matter content, where they lay their eggs. The eggs hatch into worm-like whitish larvae up to a quarter inch in length with distinctive shiny black heads. The larvae feed on the decaying organic matter in the growing medium, but sometimes attack the plant roots. A large scale attack can result in stunting of the plant, and it is also thought that these insects may play a part in encouraging rot diseases. Avoid overwatering, and allow the soil to dry out, especially on the surface, between waterings. Sticky yellow cards are useful for monitoring their presence and may effect some control. Biological controls are often used, such as Bacillus thuringiensis (BT), predatory mite (Hypoaspis) and beneficial nematodes Steinernema or Heterorhabditis. To monitor for the presence of the larvae place a few peeled raw potato slices about a quarter to half inch thick on the surface of the growing medium for several hours. This will attract the larvae and give you an indication of how extensive the infestation is and whether or not your control measures are working.

larvae

Larval Stage

adult gnat

Adult Gnat

G Terms

GAMETE

A mature germ cell possessing a haploid chromosome set and capable of initiating formation of a new individual (the zygote) by fusion with another gamete; egg or sperm.

GENE

Any hereditary element carried on the chromosomes, and sometimes in the cytoplasmic organelles, by which the characteristics of the plant are determined. Also see terms: Cytoplasm, Organelle.

GENERATION

In hybridizing, F1 refers to the first generation seedlings resulting from the cross of two different cultivars. The F2 generation refers to the seedlings resulting from breeding F1 plants to each other.

    Daylily A  Daylily B   Daylily A   Daylily B
       |             |               |               |
       |             |               |               |
       F1 Generation          F1 Generation
          |                          |
          |                          |
          --------F2 Generation-------
GENETIC DRIFT

Changes in gene frequency due to chance fluctuations. A tendency for change in the genetic composition of a population due to random mating; may cause drastic changes in small populations.

GENOME

A complete set of chromosomes, or of chromosomal genes, inherited as a unit from one parent. One haploid set of chromosomes with the genes they contain. Also see: ChromosomeHaploid.

GENOTYPE

Genetic constitution of an individual or group, deduced from data provided by breeding experiments; the entire genetic makeup of an individual.

Individuals of the same genotype breed alike.  See Phenotype.

GENUS

A category of classification ranking between the family and the species.

For example, the several species of oak collectively form the genus Quercus; of daylilies, the several species plus the many cultivars form the genus Hemerocallis; of horses, asses (note the comma between the two preceding words) and zebras, the genus Equus. See Hemerocallis.

GERMINATION

When environmental factors such as temperature, moisture, oxygen and sometimes light are favorable. a viable seed will begin to grow, or germinate, as long as it is not in a state of dormancy. The radicle, a rudimentary root, emerges from the seed first followed by the plumule or first shoot. Germination is either hypogeal (cotyledon/s remaining below ground) or epigeal (cotyledon/s emerging above the soil surface). The following image shows both types of germination in monocot and dicot seedlings. Daylily seed germination is hypogeal, with the single cotyledon remaining in the seed below the ground.

germination examples

GRASSHOPPERS

grasshoppers belong to the insect Order Orthoptera. Most are from one to two inches in size and either green, brown or yellow in color. They damage plants by consuming leaves and stems and are more of a problem in areas where the annual rainfall is from 10 to 30 inches. Eggs are usually laid in the soil in late summer/fall, so cultivating the ground at that time may reduce their numbers. Mulching may help, and natural enemies will take their toll. Rows of seedlings etc. can be covered with floating row covers. However, in general these pests are hard to control where they are numerous enough to cause significant levels of damage.

grasshoppers

H Terms

HALO

An eye that is relatively narrow or indistinct.

Halo

HAPLOID
  1. Having just one of the basic set of chromosomes of the ancestral species. In all daylily species that have been studied, the haploid set has 11 chromosomes.
  2. The haploid number is the total number of chromosomes in a single set.
HARDY
  1. In the north, a plant that is not adversely affected by cold temperatures and can grow, increase and perform well in a particular zone or zones. Some plants also need to be hot-weather hardy (ie: Texas, Arizona and Florida).
  2. A term used to describe a plant that can survive and grow in specific adverse climate conditions, ie: cold hardy or drought hardy.
HEMEROCALLIDACEAE (hem err oh kal ahh DAY see eye)

The genus Hemerocallis was assigned its own family name in 1982 by Dahlgren and Clifford. (See pp. 36-39, “Biosystematics,” by Barr The Daylily Journal, vol. 42, no. 2, fall 1987.

HEMEROCALLIS

The scientific name for the daylily. (From the Greek hemera day + kallos beauty). Originally the genus Hemerocallis was placed in the lily family, Liliaceae, but more recently it has been moved to the family Hemerocallidaceae.

HEMEROCALLIS GALL MIDGE

Contarinia quinquenotata is a small fly which has been a pest of daylilies in Europe for several decades and was identified in British Columbia, Canada in the Summer of 2001.   It is now reported to have crossed the border into the north-western United States. Damage in BC is evident between April and July depending on location. Maggots develop inside daylily flower buds causing them to become inflated, distorted and unable to open properly.  Some buds may dry up.   Reports indicate that in some cases clumps may be so badly affected that few buds open normally.  Early flowering daylilies are typically the most heavily infested and egg-laying may have ceased by the time later flowering daylilies are forming buds, allowing them to escape much of the damage. Infested buds may contain from one or two up to a hundred or more small white legless larvae up to around 0.12″ in length which, when sufficiently mature, fall to the ground where they overwinter.  Thus far it appears this insect only has one generation each year.  In spring they emerge as adults and fly to daylily buds to lay their eggs.  Because they are inside the galled buds, larvae are protected from contact insecticides.  Also, since the adults are flying for several weeks each season, it will be difficult to provide sufficiently continuous contact insecticide coverage to prevent egg-laying. Treatment involves removing affected buds as soon as it is obvious that they have been attacked.  These buds must then be destroyed so that the maggots within them cannot continue their life cycle.  Some gardeners destroy the maggots by burning the infested buds, but other alternatives need to be determined where burning is not possible.   Do not compost infested buds unless the larvae have already been killed by some means. (It is likely that collecting infested buds daily into a plastic bag and placing the bags of buds in a deep freezer for at least two days will kill the larvae, but this needs to be verified).   Some gardeners use early flowering daylily cultivars particularly favored by the midges as “trap plants” to assist in collection of infested buds.  Daylilies purchased in pots or with intact budded scapes are more likely to introduce the pest to a new area than daylilies acquired bare-root and without scapes.

larvae

Gall Midge larvae magnified.

midge

Close-up of affected bud with maggot indicated by arrow.

Additional information from the Royal Horticultural Society available here.

Pesticide research report from RHS/AHS study available here:

HISTORIC DAYLILY

All daylilies registered on or before 1980. This is a “rolling” date which extends by ten years every decade, i.e. in 2020, the date will change to 1990.

Some members of the AHS collect and display historic dayliies.  Look under AHS Display Gardens on the AHS Home Page menu.  Historic Daylily Display Gardens are listed within their own AHS Regions and are additionally distinguished with salmon colored cell backgrounds.

HOMOZYGOTE

An individual whose chromosomes bear identical genes of a given allelic pair or series. Homozygotes produce only one kind of gamete with respect to a particular locus and, therefore, “breed true.”

HOSE-IN-HOSE DOUBLE

“Hose-in-Hose” doubles have extra whorls (layers) of petals so that there appears to be a flower within a flower.See also: double, floral whorl

hose in hose double

HYBRID
  1. An individual descending from crosses between two or more species. (This is a botanical definition that is also widely used in horticultural commerce.) While in the AHSwe may loosely refer to the results of our crosses as hybrids to distinguish them from the original species, they are more appropriately referred to as cultivars if registered, and seedlings if not registered.
  2. The first generation (F1) from crossing differing true-breeding parents to produce uniform non true-breeding offspring with hybrid vigour. This is a specialized plant breeding definition that does not apply to any registered daylilies. However, it does apply to many hybrid crops such as tomatoes and corn.
HYBRIDIZER

In the world of daylilies, a hybridizer is one who breeds daylilies.

I Terms

INBREEDING

Inbreeding refers to any breeding technique in which the parents are related to each other. The most intensive form of inbreeding is selfing or self-pollination in which both parents are the same plant. Inbreeding is used to increase the number of homozygousgenes. It reduces the amount of genetic diversity and can accentuate both positive and negative traits. Inbreeding can involve random or selected parents, and this would have an effect on the development of homozygosity. See also: Linebreeding, backcross.

Chlorosis

INTRODUCED

Interveinal chlorosis is a yellowing of the leaves between the veins with the veins remaining green. In plants with strap-like leaves such as the daylily this results in a striped effect. While there are several possible causes, this symptom frequently indicates a nutritional imbalance. The accompanying image illustrates a daylily exhibiting interveinal chlorosis. In this particular case, leaf tissue analysis indicated the cause was probably manganese deficiency induced by high soil pH.

J Terms

JAPANESE BEETLE

Often reported to be present in gardens with daylilies but not necessarily feeding on them significantly, perhaps preferring other plants, Popillia japonica is an introduced pest which was first seen in North America in 1916 in New Jersey. It now occurs in China, India, Japan, Korea, Russia, and portions of the USA and Canada. The adults eat flowers, foliage and fruits of around 275 different plants. The larvae feed on roots, especially grasses. Japanese Beetles are present in at least parts of the following States: Alabama, Connecticut, Delaware, DC, Georgia, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia, West Virginia and Wisconsin. The adult is oval in shape and a little less than half an inch in length, metallic green with copper wing covers which are marked with lengthwise fine stripes. The grubs are whitish with brown heads and usually measure under one inch; their damage is detailed under White Grub. The adults feed during the day, preferring those which are warm and sunny, and chew on foliage and flowers, with often just the veins of leaves remaining. They tend to feed in groups, and there is one generation a year. Control measures include handpicking (shaking beetles from plants early in the morning when they are sluggish and then destroying them), and applying milky spore disease or beneficial nematodes to turf to reduce the numbers of larvae. Neighborhood campaigns are often recommended.

Japanese Beetle

L Terms

LARGE-FLOWERED DAYLILY

A blossom that is 4.5 inches or greater in diameter. A classification used at AHS Exhibition Shows.

When photographing large flowered daylilies it is often useful to include a familiar object such as a ruler or coin to judge the relative size.  See the images below and to the left for reference.

Large

LEAF, LEAVES

A lateral outgrowth from the crown of a daylily plant; each leaf is a single unit of the foliage of a daylily. A group of leaves growing from the same central crown create a fanor ramet. The leaves principle function is the manufacture food for the plant via photosynthesis.

LEAF STREAK

A fungal disease which affects the leaves of daylilies. It is caused by Aureobasidium microstictum*, however an injury to the plant may be required for infection to take place – pest damage, for example. Symptoms include yellowing along the central leaf vein followed by browning, and reddish-brown spots. The damaged areas may join together and spread along the leaf in streaks, and infected leaves may eventually die. Cultivars vary in their susceptibility to leaf streak. Minimize overhead watering and avoid working among the plants when the leaves are wet.

Leaf StreakLeaf Streak

LEAF HOPPER

there are several different species of leafhopper in the family Cicadellidae, but none have been reported as significant pests of daylilies. They are seen on daylilies from time to time, however, so are included here for identification purposes. Leafhoppers are usually less than a half inch in length and mostly cream, yellow, green or brown in color. Typical feeding damage on other plants involves piercing leaf tissues and sucking out the juices, resulting in whitish or yellowish stippling, and sometimes stunting and distortion with curled brown leaf tips and edges. Leafhoppers are important vectors of a number of serious plant diseases. They often run sideways when disturbed, or hop away. There may be two to five generations a year. If control is considered necessary, a forceful spray of water from a hose may remove young leafhoppers which cannot yet fly. Insecticidal soap should also be effective.

Leaf Hopper

LEAF MINER

In the last few years, reports of leafmining damage to daylily leaves have been received from several states.  This damage appears as whitish meandering, serpentine trails caused by larvae feeding between the upper and lower surfaces of daylily leaves.

leafminer

In 2011, specimens were reared and identified as Ophiomyia kwansonis Sasakawa, an agromyzid fly not previously known outside Japan and Taiwan. As of January, 2014, positive states are: AL, AK, CT, DE, FL, GA, IL, IN, KY, LA, ME, MD, MA, MS, MO, NH, NY, NC, OH, OK, PA, SC, TN, TX, VA, and WV.  It has also been found in Europe, Slovenia. (see link below).

The small, pale yellow larvae (up to 5mm) travel up and down in leaf blades, leaving long mines which become progressively wider as the  larvae grow.   This damage remains until the leaf dies.  Pupation occurs  in the larval tunnel, with the pupa appearing like a small (3-4mm), tan rice grain, under the surface, often near the leaf base.

Leafminer PupariumrumLarva

The adult fly (3-4mm) is small, black, and rather stocky with broad triangular
clear wings. Adults may be seen walking up and down daylily leaves or resting on blooms.  There may be one to several generations per season, depending on your growing region.  The species might overwinter as pupae in crowns or dead leaves.  No effective chemical control methods have been formally tested yet. Larvae and pupae would be unaffected by contact insecticides which would likely kill predators and tiny wasp species that have been found to attack this pest.

Leafminer Fly

Removal and destruction of infested leaves can reduce fly numbers in the garden. However, larvae have also been found in naturalized roadside daylily populations.

Careful examination of newly purchased daylilies will enable visibly infested leaves to be removed and destroyed, reducing the potential for bringing the pest into one’s garden. Unfortunately, small larvae can easily be overlooked in the pale tissue at the plants’ base. As more information becomes available, this entry will be further updated.

We would like to thank Gaye Williams of the Maryland Department of Agriculture, Plant Protection Section for assistance with this update. Further details concerning this pest can be found in the National Plant Diagnostic Network Newsletter September 2011 at http://entnemdept.ufl.edu/hodges/september_2011.pdf.

Gaye would also appreciate anyone seeing daylilies with leafmining damage contact her
and send photos (not specimens), so she may track the spread of this pest.

Gaye Williams
Md. Dept. Agr.-Pl. Prot. Sect.
50 Truman Pkwy
Annapolis, MD 21401
p-410 841 5920
gaye.williams@maryland.gov

Leafminer

Line Breeding

These apparently similar terms are typically used differently, line breeding being less well defined than linebreeding.

LINE BREEDING commonly involves the creation of a population of similar or virtually identical plants which is referred to as a “line”. These plants may have been selected for common desired characteristics (such as a purple line or a tall, spidery purple line). A “line” may be inbred (closed), partially closed, or created with minimal inbreeding.

LINEBREEDING, all one word, is a well-defined term used in animal breeding for the crossing of parents which both trace back in their pedigrees to a specific named ancestor. For an individual to be described as linebred it must be possible to name the ancestor to which it has been linebred.

Locule

One of the chambers or spaces in a daylily capsule. There are normally three locules, but polymerous daylilies have four or more.

locule

Cross-section of an immature ovary showing the three locules, or chambers, containing the ovules that will become seeds.

Lopidea Confluenta

Lopidea confluenta (no common name) is a “true bug” from the Miridae family of plant bugs and resembles the phlox plant bug (L. davisi). It has been reported to cause flower bud abortion in daylilies and iris in some areas, however no significant damage was noted in the garden where these pictures on daylily were taken. Being a true bug, it feeds by inserting a “beak” into plant tissues and therefore would not be responsible for chewing injuries. If found to cause damage significant enough to merit control, insecticidal soap may be used where the label permits.

There are several other similar bugs occurring in gardens, such as the boxelder bug and milkweed bugs.

Lopidea confluent

M Terms

Meiosis

The second of the two fundamental cytological and genetic events in the sexual cycle, the first being mitosis. Nuclear divisions in which the diploid or somatic chromosomenumber is reduced by half. The mechanism by which the chromosome number is reduced from 2n to n and in which segregation and independent assortment of genesoccur. Also see Mitosis.

Meristem (Tissue)
  1. A formative plant tissue usually made up of small cells capable of dividing indefinitely and giving rise to similar cells or to cells that differentiate to produce the definitive tissues and organs; an undifferentiated cellular region in plants characterized by repeated cell division. (The meristem is a critical location for introducing colchicine when attempting to convert a diploid daylily to a tetraploid. This method converts a mature plant, whereas other methods may convert sprouting seeds.)
  2. Terminal Meristem – a point of growth above the crown in a daylily where critical growth occurs – from this point crown tissue develops downward and leaf tissues develops upward.
  3. Meristem tissue: Mitotically active, undifferentiated plant tissue from which all other tissues are derived.

meristem

Midrib

The principal lengthwise vein of a leaf or of a perianth segment (petals and sepals). On the perianth segments the midribs may be the same color as the segment or of a contrasting color as in the example photo below.

Blueberry Queen

Midrib Crested

See Cristate.

Milkweed Bug

Because both large and small milkweed bugs are frequently seen on daylilies, they are included here for identification purposes even though it is not yet clear whether they are actually doing any damage to the plants. They both belong to the Seed Bug family, Lygaeidae, and are considered to feed mainly on milkweed seeds by inserting a beak into the seed and injecting an enzyme to aid in digestion. The toxins contained in milkweed do not affect them, but ingesting them results in the bugs becoming unpalatable to potential predators. They occur throughout most of North America. The large milkweed bug, Oncopeltus fasciatus, often appears in large numbers near buildings in a similar fashion to the related boxelder bug, for which it is often mistaken. It is roughly half an inch in length. The small milkweed bug, Lygaeus kalmii, is slightly smaller and has a somewhat different black and red pattern often with two small white dots at the rear. Both produce one or more generations a year. They are frequently observed mating, facing away from each other, and remaining in this position for up to half an hour or more. No controls are suggested at this time in view of the current lack of knowledge regarding the significance of their presence on daylilies.

beetlebeetle,ilkweed bugs

 

Millipede

These are not insects, but hard-shelled wormlike creatures in various shades of gray or brown, with many legs. They are often mistaken for WIREWORMS. Millipedes are slow moving, usually about an inch and a half long, frequently curling up when disturbed. There are several different species and they are generally considered beneficial, most living on decaying vegetation and manure and a few on insects. But they are known to attack plants on occasion, sometimes feeding on roots, tubers, fruits, seedlings and large seeds and possibly introducing disease pathogens. They prefer dampness, darkness and lots of organic matter. Reducing mulches may help. Although millipedes can be quite damaging on occasion, control is not usually considered to be necessary.

millipedesmillipeeds

Miniature

Daylilies with flowers less than three inches in diameter. They may be on dwarf, medium or tall scapes.

When photographing especially small flowered cultivars, it’s often helpful to include a familiar object such as a coin, ruler or lens cap in order to judge the size of a bloom.  See the examples below and to the left for a comparison of relative sizes.

miniature

Mitosis

A process that takes place in the nucleus of a dividing cell that results in formation of two new nuclei, each having the same number of chromosomes as the parent nucleus.

Monocotyledons, Monocots

One of the two major types of flowering plants, or angiosperms. The monocotyledons are so named because the embryo in the seed has a single cotyledon (seed leaf). The cotyledon may remain in the seed after germination as in a daylily, or emerge above the soil surface as in an onion.

Most monocots have parallel veins in their leaves. (Trillium is an example of a monocot that does not have parallel leaf veins.). Their flowers, as found in nature, usually have three sepals, and petal count is usually three or multiples of three. (One exception is grasses, which have a totally different floral structure.)

Examples of monocotyledons are the grasses, such as rice, corn, wheat, and sugar cane. The palms, orchids and lily families are also examples of monocotyledons. Daylilies are monocots. See also: Dicotyledons.

Monoploid

An individual having a single complete set of chromosomes. Also the fundamental number of chromosomes comprising a single set. Also see synonym: Haploid.

Mulch

A protective covering spread over the soil around the base of plants to retard evaporation, to control temperature, or to suppress weeds. A mulch may be organic (ie.: pine straw, compost, wood chips) or inorganic (ie.: landscape fabric, stone, or plastic.)

Multiform

A protective covering spread over the soil around the base of plants to retard evaporation, to control temperature, or to suppress weeds. A mulch may be organic (ie.: pine straw, compost, wood chips) or inorganic (ie.: landscape fabric, stone, or plastic.)

1234

Mutation, or Sport

A plant that has acquired a new characteristic, caused by a chance shift in its genetic makeup, which may or may not be stable and can be passed on to its offspring.

N Terms

National Convention

Annual gathering of members of the American Hemerocallis Society at which the Society’s business is conducted. Other meetings of the AHS Board of Directors may be held at other times during the year as events dictate. Typically the convention also features garden tours, awards banquets and judge training sessions.

Nocturnal (Bloom)

flower that opens sometime after late day and remains open during the night and perhaps all or part of the following day (in which case it may also be an EXTENDED bloomer.) Also see: Extended.

citrina

Node

The point on a scape where floral branching or a proliferation may emerge, or the point on a rhizome that can develop roots and send up a new fan. Also see: DivisionFanProliferationRametRhizome.

O Terms

Organelle

A specialized cellular part that is analogous to an organ.

Outcross

In hybridizing, bringing a cultivar from a separate genetic pool (the “outside”) into a particular “line” of one’s own hybrids for the purpose of incorporating a characteristic deemed desirable.

Ovary

The central reproductive organ around which the other flower parts are arranged. Located at the base of the pistil; where the egg cells are formed and where the seedsdevelop. A long style extends from this and is swollen and flared at the tip to form the stigma, which receives the pollen. Also see: PistilStyleStigma.

ovaryopen

Overlay

Used in two ways: 1.) to describe texture for “a flower with a velvet-like suface, or 2.) in reference to color for “a flower with another color over the basic color.” Also see: DustingWash.  All three terms are somewhat interchangeable.

overlay

Ovule

Structure within the ovary of the pistil of a flower which becomes a seed.

Ovule and seed

Ovum

A female gamete. The egg cell.

P Terms

Pattern

A daylily that exhibits variations in hue, value, or saturation of the base, midrib, or throatcolor, in such a way that a design is created beyond that of a bold or solid eye, band, haloor watermark, with or without simple picotee edging. This type of “patterning” includes, but is not limited to, daylilies with concentric rings or feathering of color within the eyezone or elsewhere. It excludes selfs, simple bitones, and simple bicolors.

The AHS annually presents the R. W. Munson Award for the best patterned cultivar as voted on by AHS Garden Judges.

Get Jiggy

Cosmic KaleidoscopeBlue Beetle

Pencil Edge

A thin line of color circling the outer edge of an eye, band, or watermark. Distinct from picotee which is only used when describing petal and sepal edges. Also used as in a penciled eye or pencil edged eye.

anther

Peony Type Double

“Peony type” doubles have petaloid (petal-like) stamens inside the normal petal whorl. Carpels may also be petaloid.

See also: double, stamens, carpel, petaloid

Peony Type Double

Perianth

The typical daylily flower consists of a funnel-shaped perianth tube and limb with six colored perianth segments called tepals arranged in two rows. The inner row of segments are petals, and the outer are sepals. Also see: Perianth segmentsPerianth tubePetal and Sepal.

Perianth Segments

A typical (not double) daylily flower has six perianth segments arranged in two rows. The three inner ones are the petals, and the three outer ones are the sepals. The term “tepal” may be used to refer to any of the six, because they are relatively undifferentiated from each other as compared to many other plants, such as roses. Also see: PetalSepalPolymerous.

perianth segments

Perianth Tube

The perianth segments are joined for a portion of their length at the base of the flowerinto a tube that surrounds the ovary.

perianth tube

Pests

Plant pests include insects, mites, molluscs, millipedes and mammals. This section will concentrate on the “creepy crawlies” you may find from time to time around your daylilies and will provide you with a quick and easy means of pest identification. Many more pests are included here than you are likely to find causing problems in a single garden. Your daylilies may well have no significant pest problems; the intention here is merely to assist you to identify and develop a little understanding of any that you may possibly encounter.

All the pests mentioned have been seen at some time in daylily gardens, but not all are likely to cause significant problems. Finding one or two should not necessarily be cause for immediate control measures to be implemented; assess the damage level first to see if it can be tolerated. Control may not be necessary, as the problem could be limited in its extent; or natural pest enemies may take care of it for you. Make sure any suspect is actually the one causing the visible damage: look at the type of injury. Pests damage plants in different ways – some by chewing, some by piercing the tissue and sucking out the plant juices for example – so knowing the typical feeding damage can help with identification of the culprit. When in doubt as to the cause of your problem, consult your local Extension or Ministry of Agriculture specialists, who will be able to assist you with diagnosis.

Maintaining your plants in good condition with adequate water and sufficient nutrients will go a long way towards helping them overcome or avoid pest problems. But bear in mind that higher nitrogen levels are considered to make plants more attractive to certain pests.

If damage occurs, consider other options before using chemical pesticides; there may be less or non-toxic approaches to the problem. Even plain water sprayed from a hose can help minimize infestations by certain pests. Where possible, less toxic controls which can be tried are listed under the individual pests. If these fail to give adequate control and damage is significant enough that a chemical pesticide is considered necessary, local advice should be sought regarding its selection, since product availability varies regionally, as does the timing of application, etc. Remember that using a chemical pesticide inappropriately can actually increase pest problems by eliminating beneficial insects, and incorrect use may damage plants.

  • APHIDS
  • BULB MITES
  • CUCUMBER BEETLES
  • CUTWORMS
  • EUROPEAN EARWIGS
  • FUNGUS GNATS
  • GRASSHOPPERS
  • HEMEROCALLIS GALL MIDGE
  • LOPIDEA CONFLUENTA
  • JAPANESE BEETLES
  • LEAFHOPPER
  • LEAFMINER
  • MILKWEED BUGS
  • MILLIPEDES
  • SEEDCORN MAGGOTS
  • SLUGS AND SNAILS
  • SPIDER MITES
  • TARNISHED PLANT BUGS
  • THRIPS
  • WHITE GRUBS
  • WIREWORMS
Petal

Top three tepals of a daylily flower that is not a double. Also see: Perianth segmentsSepal

petal

Petaloid

An adjective that indicates that a plant part resembles a petal. Often used incorrectly as a noun. See also: petal

petaloid

Phenology

A branch of science dealing with climate and the periodic biological response to it; specifically in botany, how factors such as hours of sunshine per day and temperature relate to periodical, or sequential, responses in bloom times of flowering plants and to early or late ripening of fruit.

Not to be confused with Phrenology, which has nothing to do with hybridizing or growing daylilies.

Phenotype

The visible aspects of a plant’s genetic makeup, usually expressed with words like “tall” or “short;” the observable hereditary characteristics.  See GENOTYPE.

Phytomelan

The carbonaceous, opaque material that usually covers the seed coat (testa) of daylilyseeds, generally giving them a black appearance. This black layer is typical of most plants in the Asparagales group of monocotyledons.

phytomelan

Picotee

A specific type of edge on a flower, where the edge is of a different color than that of the flower’s base color. Picotees can have borders or margins which are lighter or darker, but they should be of a contrasting color, i.e., white edge on a red flower or red edge on an eyed flower. The only criterion is that the edge be of a contrasting color as the base of the flower; it can sometimes take bizarre shapes as well as hooks, horns, teeth, bubbles, braids, or fringe. All picotees are edges, but not all edges are picotees. All picotees are picoteed edges.

picotee

Pie Crust

A descriptor used for ruffles on petal edges; usually indicating that the ruffles are very evenly spaced and evenly alternate between raised and lowered petal edges, like a decorative pie crust.

Pinching

Applies to floral segments with sharp folds giving a pinched or folded effect. See also: Crispate, Unusual Forms.

pinched cristpate

This is the perfect example of a Pinched Crispate. Petals severely pinched or folded, with the crease running back to the throat. The sepals are nicely curled.

pinched crispate

This is a Pinched Crispate. Even though the pinching occures only on the outer 1/3 of the petal, it is clearly pinched. That qualifies it as a Pinched Crispate.

Pistil

The central female reproductive organ around which the other flower parts are arranged. At the base is the ovary, where the seeds develop. A long style extends from this. The tip is swollen and flared to form the stigma. The stigma receives the pollen. Also see: OvaryStigmaStyle.

pistilpistil parts

Pleated

A form of sculpting in which the petals have a deep longitudinal crease on each side of the midrib. These creases cause folding of the petal upon itself creating a raised platform extending from the top of the perianth tube and ending between the throat and the petal tip.

Pleated

Ploidy

The number of sets of chromosomes within a cell or organism. Further referred to by the number of sets: one set is a haploid, two sets is a diploid, three sets is a triploid, four sets is a tetraploid, etc. See also: chromosomes.

Pod

The fruit of the daylily in which seed develops and ripens. Technically, it is a “loculicidal capsule,” meaning that its walls become dry and then split when the seeds are ripe as shown below. Pods form if the flower has been fertilized. If you deadhead your plants, they will not form pods. See also: Deadhead, locule, capsule.

podspod and seed

Pod Parent

The parent plant that contributes the female reproductive cells. In hybridizing, the parent that forms the pods where the fertilized seeds develop and ripen. See Pollen Parent.

Pollen

The haploid, dust-like yellow material containing the sperm cells formed at the end of the flower’s six stamens within the anthers. Also see: AntherHaploidStamens

pollen

pollen

Pollen Parent

The parent plant that contributes the male reproductive cells, i.e., the pollen. In hybridizing, the parent whose pollen is placed on the stigma of the plant that will become the pod parent. See Pod Parent.

Polychrome

Flowers blending and intermingling many colors without distinct bands.

polychrome

Polymerous

Polymerous is an adjective used to designate a daylily with more than the normal number of segments in each floral whorl, i.e., more than the normal three sepals(usually four or five) in the outer whorl and more than three petals (usually the same number as sepals) in the inner whorl. Polymerous daylilies have the extra sepals and petals evenly spaced in their respective whorls, unlike double daylilies in which the extra petals or petaloid stamens are stacked upon or lie above the ordinary petals. Moreover, polymerous daylilies have extra stamens; eight if there are four petals or ten for five petals, rather than the usual six. Most polymerous daylilies have the same number of carpels in the pistil (and therefore the capsule) as there are petals. See also: floral whorl, sepal, petal, double, petaloid, stamen, carpel, pistil, capsule, segments.

In order to conform to current botanical usage, AHS has adopted this term in place of “polytepalous” and “polytepal”.

polytepalpolypolypoly

Polymorphic

Having, assuming, or occurring in various forms, characters or styles; a capacity for wide variation.

Polyploid

A plant having three or more sets of chromosomes in each cell. See TetrapoidTriploid.

Polyploidy

The number of sets of chromosomes in each cell.

Polytepal

See Polymerous.

Proliferation

A leafy shoot from a node or bract found on scapes of many cultivars. Proliferations may be rooted to form a plant (clone) identical to the mother plant. Small roots often form and occasionally a flower is produced while the proliferation is still on the scape. In the image below the upper proliferation has formed at the bract.

Read Lee Pickles’ article: Proliferations…My Way.

proliferations

Q Terms

Quilling

Applies to floral segments that turn upon themselves along their length to form a tubular shape. Also see: CrispatePinchingTwistingUnusual Forms.

Quilled Crispates

See below for quilled crispate illustrations.

quilledQuilling - Asterisk

R Terms

Radicle

The rudimentary root of a seed’s embryo. See also: germination, cotyledon.

Ramet

Refers to individual plants in a clump, each portion of which is identical with the original parent plant. Also see: FanDivision. Terms are interchangeable.

ramet

Reblooming, Reccurent, Remontant

Having more than one cycle of flowering per year.

Recurved

Term used to describe a blossom’s appearance. Petals reflex back toward the base, giving a rounded ball-like appearance.

recurved

Region

A specific geographic area that is composed of several states, provinces and/or nations. There are 15 regions designated by the American Hemerocallis Society, each governed by an elected Regional President.

Regional Meeting

An annual gathering of members of each region to conduct the business of the region.  Most Regional meetings also include garden tours.

Some AHS Regions meet more than once a year.  Others host Regional Symposiums, often in the winter months, which are centered around educational presentations, rather than garden tours.

Registered

A cultivar has been registered when its description and an acceptable name have been approved and published annually in a printed publication of general distribution (The Checklist) by the registrar, who is appointed by the American Hemerocallis Society, the official international authority for all Hemerocallis registrations. The name(s) of the originator is also recorded. Only one cultivar may be registered under a given name.

Relief

A form of sculpting characterized by vertically raised ridges that extend from the throatand project from the petal surface. The ridges may grow parallel to the veins, or they may radiate outwards from each side of the midrib. (Relief forms have been referred to as “repousse”, “carved” and “embossed” in The Daylily Journal.)

relief

Parallel ridges between veins.

embossed

This is an example of ridges that radiate from the midrib.

carved

This is an example of ridges that radiate from the midrib.

Reverse Bitone

Flower with lighter inner segments and outer segments of a darker color. See: Bitone

reversed bitone

Rhizome, Rhizomatous
  1. An underground stem which grows outward from the plant, eventually emerging above ground as a shoot that forms a new plant of the same cultivar; roots and additional shoots can also be produced along the rhizome.
  2. Said of a plant that generates new plants from elongated underground stems called rhizomes.  Example, H. Fulva “Europa”.

Roll your cursor over the image below to see the rhizome highlighted.  This is growing between the roots of two separate plants but joining them together underground.  The second plant formed at the end of this rhizome.

Rhizome Photo

Robin

One of several groups ranging from 6 to 12 people to more than 1,300+ on the AHS E-Mail Robin, who write or discuss daylilies via continuing “flights” of letters on a given subject.

The E-Mail Robins begain in 1994 with the general interest AHS E-Mail Robin.  Since then many other E-Mail Robins have sprung up to dicsuss specific aspects of daylilies and related information.

AHS Affiliated E-mail robins: Contact group leaders for more information about how to join these groups. Or contact Round Robins Chair, Judie Branson at: roundrobins@daylilies.org

Roots

A part of the plant (usually underground) whose function is to act as support and anchorage, as a place of food storage and the primary organ of water and mineral absorption.

Some daylily roots are fibrous or cord-like, others very fine; some have conspicuous spindle-like thickenings (used primarily for water storage) as in “Europa.”

roots

Ruffled

Term used to describe the tissue on a segment’s edges, resulting in a wavy appearance. Ruffling may be very loose and deep or tightly compressed.

ruffled

Rust

A fungal pathogen that attacks daylilies.

Daylily rust is caused by the fungus Puccinia hemerocallidis and affects the leaves and scapes. It is not a new disease of daylilies, having been reported previously in China, Taiwan, Korea, Japan and Russia (Sakhalin, Kuriles and Siberia*). Unfortunately, the disease has now arrived in North America, and was first identified in the southeastern United States in August 2000.  In nature, the main method of rust spread is by wind borne spores.

rust images

Large image of infected plant

rust images

Close up of pustules on leaf

rust images

Rust pustules on daylily scape.

rust images

Top side of infected leaf.

Reports from AHS members indicate that in North America daylily rust has successfully overwintered in USDA Hardiness Zone 7 and milder. At the current stage of our knowledge, it is safest to assume that if any daylily foliage remains green through the winter in an already infected garden, there is a possibility the rust could survive inside those leaves. In very mild winter climates the familiar yellow-orange powdery “summer spores” (urediospores) produced from the spots (pustules) on daylily leaves may cause repeated infection cycles year round. A spore is similar to a plant seed, and like a seed requires moisture and appropriate temperatures in order to germinate. It is not yet known how long daylily rust urediospores can remain alive on leaves until conditions become suitable for germination and infection, or exactly how far they can travel on the wind to new daylily leaves. Rust spores can often travel many miles on air currents.

Rust diseases may also survive winter as mycelium (the strands which form the body of the fungus inside the leaf) but this can only take place where some infected leaves remain alive through the winter such as in milder climates, or where there is protection from greenhouses, deep snow cover, heavy winter mulch, or proximity of infected plants to the warming walls of a house, for example.

Another means by which rusts can overwinter is in the form of “winter spores” (teliospores). These are dark colored spores which most commonly appear at the end of the growing season in response to shorter days and cooler temperatures. The spots and streaks containing teliospores on a daylily leaf are blackish, in contrast to the more familiar orange pustules of urediospores. “Winter spores” are hardier and more durable than the “summer spores” and lie dormant on dead daylily leaves over winter. In the spring they germinate to produce another type of spore but this cannot infect daylilies. Instead, these new spores must be transported by the wind or other means to a plant of the alternate host, Patrinia, which is a perennial plant also of Asian origin. After completing the next stage of the life cycle on a Patrinia plant, the rust can then pass back to daylilies. Thus it is possible that in climates where the rust cannot survive the winter as mycelium or urediospores, it may still be able to continue the infection in the subsequent year if there is a plant of Patrinia in the vicinity.

Patrinia is not common at the moment in North America, but several species are being offered for sale both as plants and seeds. Not only does it pose a threat to daylilies as far as overwintering of the rust is concerned, but the rust life cycle stage on Patrinia is a form of sexual reproduction which may increase the chances of daylily rust becoming able to infect currently resistant daylily cultivars. However to date we are not aware of any patrinia plants having been infected with daylily rust in North America. At one time, Hosta was also thought to be susceptible to daylily rust, but further research has shown this is not the case.

When acquiring new daylilies, whether by trade or purchase, it should be born in mind that these plants could be carrying a rust infection even though it isn’t necessarily visible at the time of receipt. There have been numerous reports of rust first becoming apparent several weeks or months after the plants have arrived. The fungus may be alive inside a leaf, or spores be hiding on a leaf, without showing any obvious signs externally. An early infection may go undetected until the rust begins to form more spores, at which time it produces the characteristic yellow-orange pustules. From this point on, the infection may soon spread throughout one’s garden or nursery. It is advised as a precaution to isolate all new daylilies well away from existing daylily plantings for several months or a growing season to minimize rust spread if they turn out to be infected.

On receipt of new daylilies, some growers are peeling the outer layers of leaves from new plants right to the crown, and then cutting the remainder about one to two inches above the crown. The plant may then be soaked in fungicide if desired. This procedure may add to the transplant and shipping shock of the divisions, and that risk should be weighed against the desire to protect one’s garden and neighborhood from possible rust infection. Although there is no guarantee this treatment will prevent rust on new plants which have been exposed to the disease, it should significantly reduce the risk. Fungicide or disinfectant treatment prior to shipping does not guarantee a rust-free plant, and overseas purchasers should not assume a phytosanitary certificate indicates a clean plant.

Check new plants daily for rust especially the undersides of the leaves. Some gardeners report missing the rust because it was not visible when looking down onto the top surface of the leaves. Early signs of rust, prior to pustule development, are leaf spots which could be mistaken for some other disorder. Rust pustules are raised, and this can easily be seen with a small magnifying glass. A few other substances on leaves may appear raised, such as other plant seeds, pollen, and even fertilizer or pesticide residues. Yellow-orange powder (large numbers of spores) comes off on a white tissue when a rust infected leaf is wiped.

Differences in rainfall, humidity, temperatures and cultural practices will cause the severity of the disease to vary between gardens. Because fungicide availability and labeling differs regionally it is best to contact your local Extension Service or Ministry of Agriculture for the most recent advice on treating daylily rust. Trial results from Drs. Buck and Williams-Woodward at the University of Georgia were published in the Spring 2002 issue of the AHS Daylily Journal. The summary indicated that “daylily rust can be controlled under greenhouse conditions by fungicide applications, in particular, mancozeb, chlorothalonil, azoxystrobin and triadimefon.” Products should be rotated to reduce the risk of fungicide resistance developing. Alternate between a systemic fungicide and a contact or protectant fungicide. Application may need to be repeated as often as every seven to fourteen days – follow product label instructions. It is often recommended to remove the foliage from all plants discovered to have rust at the first sign of infection, cutting just above the soil level. Similarly cut all apparently healthy plants in the vicinity. However, if the infection continues after this initial cutting back, it is not recommended to continue repeatedly removing all the foliage. For those who do not wish to use fungicides treatment may be limited to continuous removal of individual infected leaves as they are noticed. Removed leaves should be destroyed, preferably by burning or burying where this is possible. Spores can remain alive for a while even on a dead leaf and spread from there on the wind. Opinions differ regarding the safety of composting infected leaves. Some people are spraying the plants with a fungicide before cutting the leaves in order to reduce spore numbers around the remaining stubs of plants, and then spraying again afterwards. Fungicide applications will not be as effective if the foliage is not removed from the plants. Because leaf moisture for several hours promotes rust spore germination, overhead watering should be avoided wherever possible. If it cannot be avoided (by use of soaker hoses etc. which keep the foliage dry) then timing should be such that the leaves remain wet for the shortest possible time – i.e. do not overhead irrigate late in the day or in the evening. Also, plant spacing should be sufficient that leaves dry quickly following rain or irrigation.

While daylily rust may kill the foliage on some cultivars, it is unlikely in the short term to actually kill the infected plant. However, it is not yet known what the effects of continuous infection will be on individual daylilies. It is possible that some may become weakened and thus susceptible to other stresses and diseases, or that bloom could be reduced. Looking into the future, steps are already being taken by some hybridizers to monitor plants for rust susceptibility in the hopes that it will be possible to breed rust resistant cultivars. Unfortunately, many Hemerocallis species are reported to be susceptible to the rust in its native habitat, so whether any of these will be useful in the development of new cultivars is not yet known.

Other leaf problems may resemble daylily rust. To identify daylily rust, leaf streak, spring sickness and other non-rust disorders that affect Hemerocallis, see the following web site hosted by AHS member Susan Bergeron: http://www.ncf.ca/~ah748/rust.html

The above site also contains much more detailed information on the life cycle (including images of the rust on the alternate host, Patrinia), fungicide information, a list of reported host species, images of the leaf peeling process for new plants, contact information for local assistance, notes from presentations by plant pathologists about daylily rust and much more which is beyond the scope of this definition. The AHS provides this link as a source of information. The AHS does not have any control of the content on the site.

We do not have all the answers about this fungus yet, but we will try to keep this page updated as new developments arise that may change growing methods, prevention methods and practices related to rust.

S Terms

Scape

A flower stalk without leaves. The daylily flower scape has no leaves except some modified leaves called bracts. The scape is the entire flower stalk above the crown. Also see: BractCrownStalk.

scapescape

Scape Blasting

The sudden bursting, splitting or severing of a daylily scape in the middle. Scape blasting is usually caused by heavy rain following a period of drought causing a rapid increase of internal pressures within the scape. Fertilization just prior to or during a swift increase in soil moisture may contribute to scape blasting. Sometimes the rupture is complete, and all blooms are lost. At other times the rupture is partial and the daylily will continue to bloom. Should the scape not separate completely, the break can be supported with ice cream stick splints and duct tape. Scape blasting has been attributed more often to tetraploids than diploids, possibly because of their thicker, less flexible cell structures.

blasted scape

The image above shows a blasted scape a few days after the scape has burst. The buds continue to be fed, but they are held on by only a small section of the original scape.

blasted scape

This image on the left shows a scape that has blasted from top to bottom (or vice versa). Most often a blasted scape resembles a spent fire cracker, with sections of the scape being blown out in a number of directions, but internal pressure can also cause the scapes to split vertically as shown.

blasted scape

This image from Karen Sherrill, shows the split scape and curls often seen in a blasted scape. The upper part of the scape is shown as well.

Sculpted

A term used to describe three-dimensional structural features involving or emanating from the throat, midrib or elsewhere on the petal surfaces. Sculpted forms belong to one of three different groups: Pleated, Cristate and Relief.

Pleated:
Petals that have a deep longitudinal crease on each side of the midrib. These creases cause folding of the petal upon itself creating a raised platform extending from the top of the perianth tube and ending between the throat and the petal tip. (Pleating has been referred to as “origami” in The Daylily Journal. See references.)

sculptedpleated

Cristate:
A term that refers to appendages of extra petal tissue growing from the midrib or elsewhere on the surface of the petals. When the extra tissue grows from the midribs, the form is called “Midrib Cristate”. (Other cristate forms have been referred to as “gothic” in The Daylily Journal. See references.)

Cristate can occur on single and double daylilies, but by itself, does not make a daylily double.

crestedcrested

Kevin Walek

Relief:
The relief forms are characterized by vertically raised ridges that extend from the throat and project from the petal surface. The ridges may grow parallel to the veins, or they may radiate outwards from each side of the midrib. (Relief forms have been referred to as “repousse”, “carved” and “embossed” in The Daylily Journal. See references.)

relief

relief

Seed

The fertilized ripened ovule of a flowering plant containing an embryo and normally capable of germination to produce a new plant.

seeds

Seedcorn Maggot

SEEDCORN MAGGOT, BEAN SEED FLY. Delia platura (previously known as Hylemya platura). This is the larva of a small fly related to the cabbage and onion maggots, and is a pest in many countries. It was introduced to North America from Europe in the 1800’s and feeds on large seeds such as peas, beans and corn, and on seedlings and young shoots of many other plants. It is also considered to transmit rot organisms.

The maggot is legless, yellowish-white, about a quarter inch long, tapered to a point at the front and blunt at the rear. It is most damaging in weather which is cold and wet and where the soil is high in organic matter. It has recently been discovered to attack daylilies, causing a rapid collapse of the affected plants. There may be several generations of maggots each year. No controls are yet established for this pest in daylilies.

delia pupae

Pupa in daylily

delia plactura

Delia platura – Maggot stage

delia adult fly

Delia Fly

delia maggot

Damaged daylily fan

Seedling

In the daylily, used to reference any unregistered plant raised from seed. A seedling may be of any size or age and may or may not be used in a hybridizing program.

Segment

A typical (not double) daylily flower has six perianth segments arranged in two rows. The three inner ones are the petals, and the three outer ones are the sepals. The term “tepal” may be used to refer to any of the six, because they are relatively undifferentiated from each other as compared to many other plants, such as roses. Also see: PetalSepalPolymerous.

perianth segments

Selection

An unnamed, unregistered seedling, but numbered and perhaps propagated. Often destined to become a named cultivar or a breeding parent in a hybridizer’s line. A seedling that has been selected from many other seedlings for further observation as a potential introduction or breeding stock.

Self

A flower having perianth segments all of the same color. The throat region can be a different color. In a complete self the segments, throat, pistil and stamens will all be the same color. Also see: Perianth segmentspistilstamenthroat.

selfself

Self-Compatible, Self-Fertile, Self-Fruitful

A plant that produces viable seed after fertilization with pollen from a blossom of the same cultivar. In other words, one cultivar will serve as both the pod and pollen parentsof the ensuing seedlings.

Selfing

Placing the pollen of one flower on the stigma of the same flower, or on another flower of the same species, variety or cultivar (taxon). An objective when selfing hybrids is to produce seeds, then seedlings, that exhibit desirable, though recessive, characteristics such as increased rebloom and fragrance.

Semi-Evergreen

Intermediate foliage behavior that is not adequately described as simply DECIDUOUSor EVERGREEN.

Also see: DeciduousEvergreen.

Senescence

The process of aging or growing old. In daylilies, this term most specifically refers to the aging process of the individual flower and the process that causes it to begin to collapse into a spent bloom, wither and dry up after a single day of bloom. From the Latin senescere “To grow old”.

senescence

After only a single day of bloom, the senescence process causes each bloom to start to break down and eventually dry up and fall away from the scape unless spent blooms are deadheaded.

Sepal

Bottom three segments of a daylily flower that is not a double. Also see: Perianth segmentsPetal.

sepal

Sexual Reproduction

A type of reproduction involving the fusion of gametes (sex cells) and their nuclei.

In daylilies, sexual reproduction creates genetically unique individual plants as the result of growing from seed created through cross-pollination.  Once a plant is grown from seed, any new divisions it produces are through vegetative or asexual reproduction and the results from this are additional plants genetically identical to the original plant.

Shoestring Root Rot

There are several different organisms that may be involved in rot diseases of daylilies, such as species of the fungi Fusarium, Phytophthora, Rhizoctonia, Pythium and Sclerotium as well as bacterial soft rot caused by Erwinia. In 2004, a fungus generally associated with woody plants was identified in diseased daylilies for the first time. Armillaria root rot infection is known most commonly as “Shoestring Root Rot” in North America because of the shoestring like structures it produces, and in some other countries it is referred to as “Honey Fungus” due to the color of the mushrooms.

The text below has been kindly written for us by Dr. Guido Schnabel of Clemson University, who made the initial identification of this disease in daylilies. This fungus is not likely to be a common cause of rot disease in daylilies but could be a possibility when gardens have been cleared from woodland, or where there are dead or diseased trees or shrubs known to be infected with Armillaria.

Root rot, Armillaria root rot:

A new fungal pathogen on daylilies. G. Schnabel, Department of Entomology, Soils, and Plant Sciences, Clemson University, Clemson SC 29634. schnabe@clemson.edu.

Armillaria root rot disease is a soil borne pathogen that primarily affects woody plants but occasionally is reported on herbaceous species. In June 2004, the disease was discovered for the first time on daylilies. The diseased plants were located in South Carolina and grown in well drained loamy soil that is supportive of Armillaria root rot disease. The site used to be woodland and was just recently cleared. Daylilies were planted around multiple hardwood stumps and an Armillaria root rot symptomatic dogwood tree.

Symptoms were similar to drought stress and included poor growth of the plant and yellowing of leaves. A cross section through the crown of wilting plants revealed necrotic areas with fan-shaped, white fungal mat growing inside. In some instances, mycelial fans were also discovered in primary roots. Black shoestring like rhizomorphs were found on and near the daylily and dogwood roots and in other places of the yard. These rhizomorphs are produced by the fungus to explore the area and look for new prey. They are initiated on a food base, such as tree stumps.

The causal organism of the Armillaria root rot disease in daylily was identified as Armillaria gallica H. Romagnesi & Marxmüller based on genetic fingerprinting. This species is most prevalent on the west coast and in the mid west of the United States but is also known to be a pathogen on trees on the east coast. It produces gill-bearing mushrooms typically in the fall at the base of infected trees and sometimes on shallow roots. The mushrooms grow in clusters, are brown, and possess an annulus (ring) around the stalk. Cultural or chemical control options have not been established for this new disease on daylilies but research is in progress.

armillaria

Armillaria Root Rot on daylily.

armillaria

Mycelial sheets in nectrotic tissue of a daylily crown.

armillaria

Rhizomorphs intermixed with daylily roots.

Siblings, Sibs

In daylilies, usually the seedlings resulting from one specific cross between two parents.

Single Form

Daylily flowers that have three petals, three sepals, six stamens and one pistil(comprised of three carpels) are known as “single” daylilies. A single daylily flower may occasionally have fewer or more (see “polymerous”) parts per whorl. Also see monocot, double.

Slugs & Snails

SLUGS AND SNAILS – are not insects but molluscs and thus belong to the same group as shellfish such as oysters and clams. Slugs usually range from a quarter inch to four inches in size, and because they don’t have the advantage of a snail’s protective shell, they have a greater requirement for damp places in which to rest during the day. They feed during the night, creating holes in foliage and chewing on leaf edges, causing them to become ragged. Feeding between the veins can cause shredding of the leaves. One can usually verify their presense from the shiny trail of slime they leave behind them on their travels. Damage can be significant, and tends to be worse in spring and fall when conditions are damper and especially where there is heavy use of organic soil amendments such as compost and manure. There are several different species. Slugs are usually gray with some darker markings, although some are more yellowish and some are almost black in color. Frequent cultivation may expose eggs and even slugs themselves to the elements and predators. Remove as many hiding places such as boards, large stones etc. as you can, although leaving a board or two and checking underneath it each day may allow you to capture and dispose of any slugs which find it a convenient resting place. Reduce mulches to minimize damp locations. Snails can be handpicked, but this may be rather more difficult (and unpleasant!) with slugs. Diatomaceous earth can be effective, and they are said to be repelled by an oak leaf mulch and certain plants such as artemisia.

slugs

Small-Flowered

Daylilies classified as small have blooms that measure 3 inches or more but less than 4.5 inches in diameter.

Spatulate

One of three definitions of an Unusual Form daylily. Floral segments are markedly wider at the end, resembling a kitchen spatula. Also see: CascadeCascading/CurlingSegmentUnusual form.

spatulate

Species

A category of classification lower than a genus or subgenus and above a subspecies or variety. A group of animals or plants that possess in common one or more characteristics that distinguish them from other similar groups, and do or may interbreed and reproduce their characteristics in their offspring, exhibiting between each other only minor differences bridged over by intermediate forms and differences ascribable to age, sex, polymorphism, individual peculiarity or accident, or to selective breeding. A distinct kind of animal or plant.

In daylilies, the species are native to eastern Asia. These are dayliles found growing “in the wild” in the locations in which they originated.

The species represent a unique breeding population in the wild, with some diversity of height, color and bud count being present. When two members of the same species cross pollinate the resulting seedlings are still considered to be of that species and are not new hybrids. Selected clones may be singled out and reproduced vegatatively as well.

citrinamiddendorffii

Commonly available species include, but are not limited to: H. minor, H. flava, H. fulva, H. multiflora, H. dumortierii, H. middendorffii, and H. altissima .

Spent Bloom

Each daylily bloom lasts a single day. The day after a bloom has been open it will have withered and melted into a condition referred to as a spent bloom. This process is known as senescence. Most daylilies will slough off these spent blooms in 2-3 days by themselves, but gardeners may also elect to deadhead their plants to remove the spent blooms. This practice makes the garden neater and also helps prevent the formation of seed pods that are not wanted.

spent bloom

Spider

A flower whose petal length is four times the petal’s width or more, a ratio of 4.0:1 or greater.

spider

Spider Measuring Methods

A spider daylily must have a petal ratio of at least 4:1. That is, the length of the longest petal (usually the bottom one) must be at least 4 times its width.

Here are two methods of measuring a spider daylily. The first method is an easy way to determine if the flower meets the minimum 4:1 ratio and can be done with the flower “on scape” without destroying the flower.

Method 1: On Scape

SpiderCURLY CINNAMON WINDMILL – Crochet
Measuring the petal width is the same for both methods. The blossom should always be “on scape” for this measurement.

Lightly lay a ruler across the longest petal at its widest point. The ruler should barely touch the petal, so as not to flatten the petal and change the width.
Width

Here the petal width is 3.1 centimeters.

In order to be a spider the length must be 4 times 3.1, or at least 12.4 centimeters.

Spider Notch
In the “on scape” method, the length of the petal is measured on the scape from the “V” where the sepals separate – indicated by the white circle above.

Total Length
Place the end of the ruler in the “V” where the sepals separate and gently extend the end of the petal out as far as it easily will go along the ruler.

See if it passes the 12.4 mark on the ruler. If it does, then the flower is a spider. Here we see the length is 15.8 centimeters, so the petal exceeds the 4:1 ratio of 12.4. 15.8 (length) divided by 3.1 (the width) = 5.09. By this method the spider has a ratio of 5.09:1.

Method 2: Off Scape.
Spider Cut
Method 2: This is the most accurate measurement. Hybridizers should use this method when registering their introductions.

1. Using the same procedure as the “on scape” method, measure the width of the longest petal at its widest point.

2. Then remove the blossom from the scape. Cut the petal away from the base of the flower at the “V” notch where the sepals separate.

Petal Length 1
Lay the petal flat on a surface and lay the ruler on top of it. That way the measurement of the length will be exact.

Petal Length 2
We see that the exact length is 16.6.

The width remains the same – 3.1. The ratio is 16.6 (length) divided by 3.1 (width) = 5.35:1.

That is more accurate than the “on scape” method which arrived at a ratio of 5.09:1. However, the difference is less than 5%. So, the “on scape” method is pretty accurate, and, in most cases, it is an easy way to determine if the blossom meets the minimum 4:1 ratio.

Spider Mites

SPIDER MITES – not insects but Arachnids, a group which also includes spiders and ticks. Spider mites are a common problem. While there are several species, the illustrated Two-spotted Spider Mite, Tetranychus urticae, is one of the more common mites you are likely to encounter, and it feeds on a wide range of plants. Since these mites are extremely small, magnification is necessary to get a good look at them. The two-spotted spider mite is pale yellow or green often with two brown spots; at times some spots may be an orange-reddish color. These pests feed by piercing the undersurface of the leaves with their mouthparts and sucking up the plant juices. When leaf surfaces develop pale speckling, a closer look may reveal patches of webbing underneath the leaves, and with the aid of a magnifying lens you will probably also notice many tiny round eggs. (See the entry on thrips for an image of these eggs.) Heavy damage causes leaves to look dry and discolored, and since spider mites are more of a problem in hot, dry conditions, this may be wrongly attributed solely to the weather. Reproduction is rapid resulting in many generations a year, and the use of certain insecticides can actually increase mite populations. They are also favored by high levels of nitrogen fertilization. Many other insects and mites feed on spider mites and their eggs, including some thrips. Keep plants sufficiently watered to prevent drought stress and frequently spray the leaves with water, especially underneath, as forcefully as possible without damaging the plants to remove and discourage the mites.

spider mites

Spider Variant

This classification no longer exists, it was eliminated in 2003. Its entry is retained here for historical and reference purposes.

This was a class that referred to a flower whose petal length was at least four times but less than five times the petal’s width (ratio of 4.0:1 to 4.99:1). Today, registrations that fell into this class are referred to as spiders.

variant

Spiderish, Spidery

Not a recognized term by the American Hemerocallis Society, but in conversation it implies that a flower has the characteristics of a spider or unusual forms, but may not fit any of these bloom forms. Also see: SpiderUnusual Form.

Sport or Mutation

A plant that has acquired a new characteristic, caused by a chance shift in its genetic makeup, which may or may not be stable and can be passed on to its offspring.

Spring Sickness

The name given to a disorder of daylilies which appears soon after growth commences following winter. One or more fans fail to maintain the same rate of growth as others in a clump, and frequently bend and grow sideways. Leaves emerge with brown ragged edges and holes, and on some fans the central leaves may wilt and detach having decayed at the base. Affected fans may grow out of the condition and even bloom, but some remain stunted or disappear although the plant as a whole generally survives. The cause has not yet been proven but the damage appears to be initiated before spring growth emerges above the ground. There is no evidence to support the popular idea that the initial cause is fluctuating temperatures after new growth has emerged in the spring.

A “task force” of AHS member volunteers is currently working on this problem, and has a developed a helpful web site to provide information on the latest developments: http://www.ncf.ca/~ah748/sstf.html _ Additional photos of Spring Sickness for identification purposes are also on this site.

stunted

Clump (foreground) stunted by spring sickness. The center leaf of the closest fan can be seen bending sideways.

bent

Fan growing sideways. Also note the brown edges.

open

Affected fan with leaves separated.

ragged

Typical “saw-tooth” ragged leaf edges.

Stalk

A flower scape without leaves. The daylily flower stalk has no leaves except some modified leaves called bracts. The stalk is the entire flower scape above the crown. Buds and blooming flowers are at the top of the stalk.  Any lateral branching or stems are also part of the stalk.  

Also see: BractCrownScape, Branching, Stem.

Stamen

Each typical flower has six stamens attached at the base of the petals. Each stamen has a stalk called the filament that ends with a two-lobed anther filled with dust-like yellow pollen. The pollen is haploid and contains the sperm cells. Also see: AntherFilamentHaploidPetals.

stamens

Stem

A slender stalk supporting or connecting another plant part, such as a scape, buds, and flowers.  The stem is a hollow cylinder of vascular tissue.

The daylily stem consists of the scape and branches. 

Sterile, Sterility

Lacking the ability to reproduce sexually.

Some daylilies are completely sterile; those that cannot accept pollen are “pod-sterile;” those which have pollen that cannot fertilize another daylily are “pollen-sterile.”

Stigma

Apex of the long style that extends from the ovary, where seeds develop, and that swells and flares at its tip to receive pollen.   Also see: OvaryPistilStyle.

Stigma

The image above shows the three lobes of a typical daylily stigma. The photo below shows a microscope view of the stigmatic hairs on a stigma that accept the pollen.

stigmaStigma 1

Stolon

A horizontal branch that grows out from the base of a plant and produces new plants from buds at its tip or nodes.

Also see: NodesRhizome.

Stoloniferous

Bearing or developing stolons.

Stomate

An opening on a leaf through which water evaporates. The opening size is deterrmined by two guard cells – one on each side. Stomates are helpful in determining whether a conversion has been successful, since the stomates are significantly larger on a tetraploid than a diploid. This, and the size of the pollen grains (which can also be measured), will help determine if a conversion has been successful or not.

Stout Silver Medal

The highest award a cultivar may receive from the American Hemerocallis Society. Only one Stout Silver Medal is awarded yearly. Also referred to as the Stout Medal.

Stout Medal

Stout Silver Medal

The highest award a cultivar can receive is the Stout Silver Medal, given in memory of Dr. Arlow Burdette Stout, who is considered to be the father of modern daylily breeding in North America. This annual award – as voted by AHS Garden judges – can be given only to a cultivar that has first received the Award of Merit not less than three years previously.

Stratification

Stratification of seeds means chilling under moist, not wet, conditions to prompt the germination of dormant seeds. (A dormant seed is one that does not germinate immediately when exposed to normal germination requirements such as adequate temperature, sufficient oxygen, and appropriate moisture).

Stratification can be accomplished in a refrigerator or outdoors, although it is better to avoid freezing the seeds during the process. The suggested temperature range (see Griesbach) for daylily seed stratification is 0°C (32°F) to 10°C (50°F), with four to eight weeks duration being sufficient. Chilling dry seeds does not achieve the same effect. Stratification causes the seeds to germinate at more or less the same time upon removal from chilling conditions, instead of spread out erratically over weeks or even months. While many daylily seeds benefit from stratification by germinating more evenly and quickly, not all daylily seeds are dormant and non-dormant seeds will germinate promptly without stratification.

Style

The central portion of the pistil between the seed-bearing ovary and the pollen-receiving stigma. Styles can be elongated like in a daylily, very long as in corn silks, or short and even indistinguishable as in some mulberries.  Also see: Ovarypistilstigma.

Style

T Terms

Tarnished Plant Bugs

TARNISHED PLANT BUG – Lygus lineolaris occurs throughout North America. (The Tarnished Plant Bug in Europe is Lygus rugulipennis, this family of bugs often being known there as capsid bugs). Lygus lineolaris is around a quarter inch in length; the adult is often seen on or in daylily flowers and on leaves, frequently ducking underneath the bloom or leaf rapidly when approached. While the adult is usually yellowish brown with an obvious triangle shape on its back, the young nymphs are green and resemble aphids when small except that they move much more quickly. The adults overwinter under leaves and other garden debris, stones or bark. They emerge early in spring on warmer days and are active in the garden into the fall. Eggs are inserted into plant tissue. There are three to five generations a year, and in the south they may be active year round. TPB’s are damaging to a wide range of plants including agricultural crops and vegetables as well as ornamentals; they feed by inserting a beak into the plant tissues, injecting a toxin, and sucking up the plant juices. While the extent of the damage they do to daylilies is uncertain, in other plants their feeding can result in injury to flower buds, causing them to abort and drop, or the blooms not to open properly. Seed pods may be attacked, causing seeds to shrivel or be non-viable, and younger pods may drop. Feeding on other plant parts may result in distortion, stunting and dieback. The adults are highly mobile, which makes them difficult to control. TPB’s are particularly partial to alfalfa, and after this is cut for hay will often then move into neighboring gardens to find alternative food. They also tend to be more of a problem in dry years. Clean up leaves and other garden debris in the fall to remove overwintering places. Control weeds which can provide food and hiding places. If necessary, spray with insecticidal soap early in the morning when the bugs are still sluggish from the cooler temperatures.

TPB

The image was taken by Ralph Underwood. Permission granted by Agriculture and Agri-Food Canada. Any additional uses of this image must be received from the copyright holder directly – AHS does not have permission to grant additional usage of this image for any purposes.

beak

This image show above show the feeding “beak” that is inserted into plant tissue to feed.

TPB

nymph

An older nymph. Note green color and how different it looks from the adults. Younger nymphs are smaller and resemble aphids but are faster moving.

size

Showing the comparative size of the older nymph on a one cent coin (U.S. and Canadian pennies are about the same size).

Taxa

Plural of TAXON.

Also see: TaxonTaxonomy.

Taxon

A taxonomic group or entity of any rank. The name applied to a taxonomic group in a formal system of nomenclature.

Also see: TaxaTaxonomy.

Taxonomy

The classification of plants and animals, according to their natural relationships. The categories (taxon) now in common use in botany are (beginning with the highest) division, class, order, familygenusspecies and subspecies or varietyIn plants, the system of Linnaeus.

Also see: TaxaTaxon.

Tepal

Refers to any of a daylily flower’s petals and sepals, its perianth segments.

Testa

The seed coat, which is the protective covering of a seed and develops from the outer layers of the ovule. Daylilies generally have a crust of phytomelan on the testa, which gives them their black color.

testa

Tetraploid

Having four sets of chromosomes in each cell of the plant (in daylilies, 44 chromosomes altogether.) That is twice the number found in the sex cells (sperm and egg).

See also Colchicinediploid , triploid.

Thrips

THRIPS – these pests are often talked about but seldom seen because of their very small size and the fact that they spend a lot of time concealed between leaves and in flowers. Not all thrips are bad. There are beneficial thrips which prey on other pests. Some thrips eat fungi. Even some plant feeding thrips can be useful at times, consuming spider mite eggs in their immature stage as illustrated in the accompanying image. Daylily thrips, Frankliniella hemerocallis, is one of several types of thrips to have been reported on daylilies. Thrips are usually yellow, orange, dark brown or black. Young thrips are most often whitish or yellow but quite similar otherwise to the adults, although adults may have wings. Thrips are less than an eighth of an inch in length, usually much smaller, and there can be many generations in a year. Damage to the leaves results in light colored patches or streaking, often with blackish thrips droppings in the vicinity. Flower bud damage causes streaks, distortion and bud drop, and scapes may develop corky lesions several inches in length. Daylily cultivars vary in their susceptibility to thrips damage. Problems tend to increase in dry weather and also where plants have been heavily fertilized with nitrogen. Keeping plants adequately watered and encouraging beneficial insects should limit thrips population levels. Insecticidal soap can reduce their numbers but may not reach those hidden deeply between the leaves.

thrips

Throat
  1. The centermost inner section of a daylily bloom where the pistil and stamens join to the back of the bloom. 
  2. Deep ‘in’ the flower is usually seen at least one different color, which sometimes greatly enhances the overall effect of a flower’s bloom. An example would be a deep green throat on a red daylily, which enhances the ‘redness’ seen by a our eyes. 
  3. The part of the bloom where the frogs, ants, earwigs and spiders hang out when you’re photographing the flower.

throatthroat

Tipped

A distinctly different color occurring on the tips of the petals or sepals.

tipped

Triploid

A plant with a triple set of chromosomes (in daylilies, 3n = 33). Triploids are usually infertile.

See also: diploid, tetraploid.

Twisting

Floral segments (petals and/or sepals) which present a corkscrew or pinwheel effect. A characteristic found in many daylilies in the Unusual Form category. Also see: CrispatePinching, QuillingUnusual Forms.

Twisted Crispates

See below for twisted crispate illustration.

quilledQuilling - Asterisk

U Terms

Undisseminated

As applied to Hemerocallis, it simply means that divisions or proliferations of a particular plant (clone) have not been distributed, and are being grown only in the garden in which the plant originated.

Unusual Form

A more recent registration class based on form, its definition states: The Unusual Form class is based exclusively on form, not on color or color patterns. The flower must have distinctive petal or sepal shapes, or a combination of both on all three petals or all three sepals. It includes three basic sub forms: crispate, cascade and spatulate. The crispate sub form is further defined below.

Pinched Crispates:

Definition: Pinching – Floral segments which have sharp folds giving a pinched or folded effect.  See below for pinched crispate illustration.

pinchedpinched

Here are two examples of a Pinched Crispate. Petals are distinctly pinched or folded.

Twisted Crispates

Definition: floral segments which present a corkscrew or pinwheel effect. See below for twisted crispate illustration.

quilledQuilling - Asterisk

Quilled Crispates

Definition: floral segments which turn upon themselves along their length to form a tubular shape. See below for quilled crispate illustration.

quilledQuilling - Asterisk

Cascade 

Definition: floral segments with narrow curling or cascading segments, resembling wood shavings) See below for cascade illustration.

quilledQuilling - Asterisk

Spatulates

Definition: (segments markedly wider at the end like a kitchen spatula.) See below for spatulate illustration.

spatulate

The purpose of this class is to recognize unusual forms whose length-to-width ratio puts them outside the Spider classifications.

The AHS makes available a list of officially registered unusual form daylilies each year. It can be downloaded free from the online database. Only daylilies that appear on this official list are eligible for entry in the unusual form section of the show.

V Terms

Variegated

Having foliage that is marked, striped, or blotched with some color other than green.

variagated

Variagated Flowers

Varied in appearance or color; having streaks or patches of a different color or colors.
May also be referred to as broken color or color breaking:

Multiple genetic mechanisms are likely involved, either singularly or in combination, in the formation of the various phenomena resulting in variegated, or broken color flowers. Presently, no genetic mechanisms have been positively identified in daylilies. Viruses can cause flower variegation in other plants but are not know to be a factor in daylilies.

Variety

A term used in the scientific naming of plants to denote a naturally occurring, distinguishable variant within a species. A variety name is written in italics, normally does not start with a capital letter, and is preceded by “var.” (for varietas), e.g. Hemerocallis fulva var. rosea.

The word variety is sometimes loosely substituted for the term cultivar by writers, however a cultivar differs in that it is a group of uniform plants maintained only by horticultural practices. A cultivar can be differentiated from a variety in plant names by the initial letters of the main words being capitalized, by not being italicized, and by being enclosed within single quotes, e.g. ‘Strawberry Candy’.

Vegetative Reproductive

Vegetative reproduction, also called vegetative cloning, vegetative propagation and vegetative multiplication, is a form of asexual reproduction in plants. This process creates new individuals without production of seeds.

In daylilies, new cultivars are created through sexual reproduction, crossing two parent plants to create genetically unique new individual plants.  Once the seed germinates and a new plant gets established, it will reproduce itself vegetatively, through new division of the crown, through rhizomes in some varieties and through proliferations.  All new plants derived through any means of vegetative reproduction are genetically identical to the original plant grown from seed.  New cultivars are always propogated vegetatively in order to be registered and disseminated.

Daylilies divide at the crown.  In the photo below, you can see three examples of new fans emerging from the base of an existing mature fan.

division example

Vein

The vascular bundles that contain xylem (water conducting) and phloem (food conducting) tissues.

Veins in daylily leaves are parallel. This is a trait that is common to many monocots.

veins

Veins in a back-lighted daylily leaf.

leaf veins

Daylily leaves showing parallel veins.

Vein

Below, cross section of a daylily petal with the veins labeled.

Vein

Veining

A color pattern on the floral segments in which the base color and the veins within these tepals are of a contrasting color.

veining

Virus

Most plant viruses are made up of nucleic acid (genetic material, usually RNA, more rarely DNA) in a protein coat. They are what is known as “obligate parasites”, in other words they can only gain nourishment from another living organism in order to grow and reproduce (a minority of fungal plant diseases such as rusts and powdery mildews are also obligate parasites). Once a virus has entered a plant, it is able to replicate by inserting its genetic material into plant cells and using them to produce more of itself.

Symptoms of viral infection may be latent (no visible affect on the plant), may reduce growth (common), or result in any of several other symptoms including visible marks on foliage or flowers such as distortion, yellowing, mosaics, spots, streaks, and mottling. There is generally no treatment available for an infected plant.

Some virus infected daylilies were recently (2005) discovered and removed from different nurseries by the Michigan Department of Agriculture. These plants had been imported for sale and it isn’t known whether other similarly infected plants have been available at nurseries or garden centers in other regions. If they have, then these plants present a risk to other daylilies and, perhaps, other plants growing in their vicinity.

The virus in question is the Tobacco Ringspot Virus (often abbreviated to TRSV), which can infect a number of different plants. However, there are different strains of this virus that may have variable host ranges and we do not, at this time, know which strain has infected these daylilies or whether it is a strain that already occurs in North America.

This virus is typically transmitted mechanically (such as during division of plants), and by vectors such as dagger nematodes, grasshoppers, melon/cotton and green peach aphids, onion thripsspider mites and tobacco flea beetle, which introduce the virus by feeding on infected plants and then subsequently on healthy ones. Some of these are known pests of daylilies and could therefore spread the disease. In some plants, this virus can also be transmitted by pollenand seeds.

Daylily gardeners are advised to watch out for the yellow blotches of this virus as illustrated below, but be aware that other conditions like pest, disease and weather damage, nutrient imbalances, and chemical injury such as from pollution or sprays may resemble virus symptoms. Currently the only way to determine for sure if a plant has a virus is to have it tested by a diagnostic service.

If you suspect a daylily in your garden may have this disease, remember that once a plant is infected with a virus there is generally no treatment and the plant will likely be infected for the remainder of its lifetime. Any divisions taken from that plant are also likely to be infected, as are any other plants subsequently divided with the same tools if those tools are not adequately disinfected between plants. Also, there is the risk of pests carrying the disease to healthy daylilies. Until we know whether the virus is pollen and/or seed transmitted in daylilies, it is safest not to use any suspect plants for hybridizing.

The usual recommendation is to destroy virus infected plants. However, it can be difficult to differentiate virus symptoms from other disorders visually, plus we do not know at this time if any infected daylilies found their way to other nurseries, garden centers or gardens in North America. Expert advice is therefore recommended before determining a course of action regarding suspect plants. It is always prudent not to purchase any daylily that has an abnormal appearance.

virus on leaves

leaves showing a virus

W Terms

Wash

In reference to color, it refers to the layering of one color over another. Is used, as in, “a flower with a wash of another color over the basic color.” Also see: Overlaydusting. All three terms are interchangeable.

washwash

Watermark

A zone above the flower’s throat which is lighter in color than the petal color.

watermark

White Grubs

WHITE GRUBS – are the larvae of various scarab beetles, family Scarabaeidae, including May, June and Japanese Beetles. They are whitish with brown heads and three pairs of legs, and are often found curled into a C shape under the soil surface. Size varies from around a half inch to two inches in length according to species. If skunks, raccoons, moles and other small animals are digging in your lawn, this may indicate the presence of white grubs. These larvae feed on roots, particularly in lawns where the turf may become brown in patches and can be rolled back like a carpet. They have been reported, however, to feed on daylily roots on occasion. This is probably most likely where a new daylily planting bed has been recently dug out of a grassed area. On a small seedling the roots may be severed just below the soil surface and the plant found lying on the ground. On digging into the soil where the seedling was growing, you may find one of these grubs and can remove and destroy it. Digging new beds in the fall and leaving unplanted until spring will expose some grubs to birds and other predators. Burying cut potatoes in the soil in affected areas is said to attract the grubs, which can then be removed every few days. Where more extensive control is required, parasitic nematodes and milky spore disease may be applied to affected areas.

white grubs

Whorl

One of the layers of modified leaves that make a flower; a complete flower has four whorls: sepals, petals, stamens, and pistil(s) from base to top. See also: sepal, petal, stamens, pistil.

Whorls

Daylily flower with some petals and sepals removed to show the four floral whorls. Frontal view below.

Whorls

Wireworms

WIREWORMS – occur in most of the world, and are the larvae of click beetles, family Elateridae. They are up to one and a half inches long, yellowish-brown with a hard, shiny, jointed exterior. Unlike MILLIPEDES, with which they are often confused, they do not curl up when disturbed, or have a large number of legs. They attack many different plants, tunnelling into large seeds, roots, stems, bulbs and tubers, and are often most numerous in new areas dug out of grass. Larvae may spend several years feeding under the soil surface before pupating and emerging as adult beetles. Preparing new planting beds in Fall and re-digging several times at intervals may help to reduce wireworm numbers by the time Spring planting time arrives. Try burying cut pieces of potato as traps, inspecting every few days. Wireworms are also controlled by predatory nematodes.

wireworm

Z Terms

Zygote

A cell formed by the union of two gametes in sexual reproduction; a fertilized egg.

Contribute

Suggest a Term

Back to Top
The American Daylily Society

5000+ Happy Members