Frequently Answered Questions
Learning starts here!
The following daylily questions and answers have been summarized from The Illustrated Guide to Daylilies, a publication of the American Daylily Society, available now on Amazon. The Daylily Dictionary, found from a link on our Home Page, is also a great resource for learning. You can also use the CONTACT US link at the top of this page to ask your own question. Our active Facebook pages are also a great source of information and up-to-the-minute photos.
The scientific name for daylily is Hemerocallis, most recently considered to belong in the plant family Asphodelaceae. Notice that the preferred spelling is “daylily” as one word. Many dictionaries spell it as two words. The word Hemerocallis is derived from two Greek words meaning “beauty” and “day,” referring to the fact that each flower lasts only one day. To make up for this, there are many flower buds on each daylily flower stalk, and many stalks in each clump of plants, so, the flowering period of a clump is usually several weeks long. And, many cultivars have more than one flowering period.
The daylily is sometimes referred to as the perfect perennial because it is:
- Available in a rainbow of colors and a variety of shapes and sizes.
- Able to survive with very little care in a wide range of climates.
- Suitable for all types of landscapes.
- Drought tolerant when necessary, with relatively few pest and disease problems in most gardens. See descriptions of pests and diseases that may be encountered .
- Adaptable to various soil and light conditions.
- Known to bloom from late spring until autumn.
The genus Hemerocallis is native to Asia. Since the early 1930s, hybridizers in the United States and England have made great improvements in daylilies. Originally, the only colors were yellow, orange, and fulvous red. Today, we have colors ranging from near-whites, pastels, yellows, oranges, pinks, vivid reds, crimson, purple, nearly true-blue, and fabulous blends. Many people are familiar with only the common yellow or orange daylilies which are often seen along roadsides. These daylilies are cultivated forms of the wild types of daylilies which have “escaped” and are growing as if they are wild. All the modern daylilies have been developed through a complicated history of hybridization among these and other wild types.
The daylily can be characterized as a clump-forming, herbaceous perennial with fibrous or somewhat tuberous roots. The daylily has four fairly distinct growing parts.
The roots of a daylily are long, slender, and fibrous. Or, they may be enlarged into spindle-shaped tubers with additional roots at their bases. The roots absorb water and minerals for use by the plant, and serve as storehouses for food produced by the leaves.
The crown of a daylily is the stem of the daylily plant. It is the solid white core located between the leaves and the roots. The crown produces leaves and scapes from its upper surface. The roots are produced from its sides and lower surface.
The leaves of daylilies are long, slender, and grass-like. They have a prominent center rib on the underside. The leaves are arranged opposite each other on the crown, giving a flattened appearance which causes the plant to be referred to as a “fan.” Multiple fans of a single plant form a “clump.”
The scape of a daylily is a leafless stalk which bears the flowers. Most have two or more branches, each bearing several flower buds. Below the branches, the stalks have a few leaf-like “bracts.” Sometimes, a small plantlet grows at the junction of a bract and the scape. This is called a “proliferation” and can be rooted to produce another plant.
Modern hybrid daylilies have a remarkably diverse color range, especially considering that the wild types from which they have been bred were only in shades of yellow, orange, fulvous (i.e., dull reddish yellow), and rosy-fulvous. Today, the only colors notably lacking are pure white and pure blue. Needless to say, hybridizers are avidly pursuing these two colors.
Basic Flower Colors
The outer portion of the daylily flower is considered to be the basic color of the flower. The present daylily color range includes:
- Yellow – all shades from the palest lemon, through bright yellow and gold, to orange.
- Red – diverse shades of scarlet, carmine, tomato-red, maroon, wine-reds, and blackish-reds.
- Pink – from pale pink through rose-pink to rose-red.
- Purple – from pale lavender and lilac to deep grape or violet.
- Melon or Cream-Pink – from palest cream shades to deep cantaloupe shades.
Notes: Buff, Brown, Apricot, and Peach are thought to be variations of pink plus yellow. Near-whites are found among the palest tints of yellow, pink, lavender, or melon.
The center area of the daylily flower is called the throat. In most daylilies, the throat color differs from the rest of the flower. Usually it is a shade of green, yellow, gold, orange, apricot, or melon.
Like the throat, the stamens may be a different color from the basic flower color and the throat color. Or, the stamens may be of matching color. Usually they are light yellow to greenish. The anthers at the tips of the stamens are often darker in color – sometimes black.
Most of the following terms are illustrated in the Daylily Dictionary – just follow the links. Modern daylilies display a complex variety of color patterns that were unknown in the original wild types. The patterns include:
The simplest pattern in which the flower segments (i.e., petals and sepals) are all the same color (e.g., pink and rose). The stamens and throat may be different.
The flower segments (i.e., petals and sepals) are a blend of two or more colors. The stamens and throat may be different.
The flower segments have an intermingling of three or more colors (e.g., yellow, melon, pink, and lavender). The stamens and throat may be different.
The petals and sepals differ in shade or intensity of the same basic color. The petals are the darker shade (e.g., rose pink), while the sepals are lighter (e.g., pale pink). A Reverse Bitone has sepals which are darker than the petals.
The petals and sepals are of different colors (e.g., red and yellow or purple and gold). The petals are the darker of the two colors.
Eyed / Banded
The flower has a zone of different color or a darker shade of the same color located between the throat and the tips of the flower segments.
- It is an Eye if the zone occurs on both the petals and the sepals.
- It is a Band if the zone occurs only on the petals.
- It is a Halo if the zone is faint or only lightly visible.
- It is a Watermark if the zone is a lighter shade that the rest of the flower segments.
On some daylilies, the edges of the flower segments are either lighter or darker than the segment color. The width of the edge can range from a very narrow “wire-edge” to as much as 1/4 to 1/2 inches.TippedThe segment tips, or more frequently just the petal tips, are a different or contrasting color from the body of the segment (sometimes for as much as one third of the length).Dotted, Dusted
The surface color of the flower appears to be unevenly distributed over the background color of the bloom rather than being smoothly applied.
- It is Dusted if the color appears to be finely misted onto the surface.
- It is Dotted if the colors are clumped into larger pools.
- Other terms used to describe uneven coloration include: Flecked, Flaked, Speckled, and Stippled.
This is the center vein running lengthwise through each flower segment. In some cultivars, the midrib is different in color from the rest of the segment. The midrib can be flush with the surface, raised above it, or recessed.
Tiny crystals in the flower’s cells reflect light, especially in the sun, to give the flower a sparkling or glistening appearance as if sprinkled with gold, silver, or tiny diamonds.
Daylily blooms have a wide array of different forms or shapes. Currently, the AHS officially recognizes the following forms for exhibition purposes: single, double, spider, unusual form, polymerous, and sculpted flowers:
Daylily flowers that have three petals, three sepals, six stamens and one pistil.
Double daylilies come in several 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) tissue on the stamens inside the normal petal whorl.
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.
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.
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.
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 (formerly Crested) and Relief.
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. Examples of a multiform daylily would be one that is both a spider and an unusual form, or a polymerous double.
Other descriptive terms of daylily form or shape characteristics are:
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. See also: Recurved
When viewed from the side of a bloom, flowers are perfectly flat except for the concave throat.
When viewed from front of bloom, flower segments have no definable shape. Segment placement may be irregular, widely spaced or floppy.
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.
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.
When viewed from side of bloom, flower form resembles a true lily. Segments rise from throat in an upward pattern with little flare.
Other characteristics often used in describing daylilies include:
Texture refers to the surface quality of the tissue structure of the daylily bloom. There are three main types of texture in dayliliesdotsmooth, creped, and ribbed.
Substance is the thickness of tissue structure, or the ability of the flower to withstand the elements. Substance varies from delicate (i.e., a thin, fragile appearance, but still durable) to heavy and leathery.
There are three categories of bloom size in daylilies:
- Miniature – Flowers that are under 3 inches in diameter.
- Small – Flowers that are from 3 inches up to 4 1/2 inches in diameter.
- Large – Flowers that have blooms 4 1/2 inches and over in diameter.
Daylily scapes with no branching have slender shoots with a cluster of buds at the top. Branching allows one scape to bear from 10 to 100 buds. Branching may be described as multiple (i.e., a number of side branches) or “three-way” with the “three” (or other appropriate figure) indicating the number of branches per scape. There are three types of branching:
- Top Branched – where the branching occurs only near the top of the scape.
- Well Branched – where the branching begins near the top of the foliage.
- Low Branched – where the branching extends into the foliage.
Most daylilies bloom for a single day, beginning in the early morning and lasting until the evening. There are three terms necessary to describe the normal and the atypical bloom habits found in daylilies:
- Diurnal – which is the normal day-blooming daylily type.
- Nocturnal – where daylilies open late in the afternoon, remain open all night, and close the following morning or early afternoon.
- Extended – where individual daylily blooms remain open at least 16 hours. Both diurnals and nocturnals may be extended bloomers.
Daylilies bloom from early spring until frost, depending on the coldness of the climate. To indicate when a particular cultivar blooms during the season, daylily growers use the following terms and abbreviations (or symbols):
- Extra Early (EE) – These daylilies are the first to bloom, and vary from March or April in the extreme South, to May or June in the North.
- Early (E) – These daylilies bloom three to five weeks prior to the mass of bloom at midseason.
- Early Midseason (EM) – These daylilies bloom one to three weeks before the height of bloom of most cultivars.
- Midseason (M) – These daylilies bloom at the peak of the daylily bloom in your own garden. This ranges from May in the South to July in the North.
- Late Midseason (LM) – These daylilies bloom one to three weeks after the height or peak of bloom in your garden.
- Late (L) – These daylilies bloom when most others have finished blooming, usually four to six weeks after the peak of the season.
- Very Late (VL) – These daylilies are the last to bloom, often late in the summer in the South, fall in the North.
- Rebloomer (Re) – These daylilies bloom more than one time during a single season. Some of these bloom early (e.g., May or June) and then repeat in the fall. Others have a succession of bloom periods, one shortly after another for several months.
Foliage traits of daylilies include color, size, habit, and cold-hardiness and heat-tolerance.
The foliage of daylilies can be blue-green to yellow-green or any shade in between.
Daylily leaves vary considerably from slender and grass-like to husky, wide, and nearly corn-like. The leaves may arch, or may stand nearly erect. The length of daylily leaves ranges from as little as 6 inches to 36 inches or more.
The winter behavior of the daylily foliage is called “the foliage habit.” For registration purposes, the foliage habit is loosely categorized as deciduous, evergreen, and semi-evergreen.
- Deciduous – The leaves of these daylilies die completely back as winter approaches. They stop growing and form resting buds at the crown, and the foliage dies down naturally and gradually. In the spring, the resting buds have a distinctive spear-like appearance as they emerge.
- Evergreen – These daylilies retain their leaves throughout the year. They do not form resting buds. Instead, they continually produce new leaves unless cold weather prevents growth. In mild climates, the leaves of evergreens remain green all winter. In the coldest climates, the foliage of evergreens nearly always is frozen back, but the crown survives if it is hardy (or well mulched).
- Semi-Evergreen – The term semi-evergreen is used to describe any foliage behavior which is not readily classed as simple evergreen or deciduous. Originally, the term semi-evergreen (or conversely, semi-deciduous) was used to describe those daylilies which retained many of its leaves and appeared somewhat evergreen when grown in the South, but lost all its leaves when grown in the North.
Cold-Hardiness and Heat-Tolerance
The cold-hardiness of daylilies is quite variable. Some are iron-clad hardy. Others are extremely tender. Cold-hardiness is not determined by the foliage habit. Evergreen, deciduous, and semi-evergreen can be anything from extremely cold-hardy to extremely tender. To avoid risk of losing a cultivar, choose daylilies which others have already grown successfully in your climate.
Plants all have a basic complement of chromosomes. Most plants are diploids. They have two identical sets of chromosomes in each cell. Polyploids are plants with more than two sets of chromosomes. A tetraploid is only one of a whole series of polyploids. Triploids have three sets of chromosomes, tetraploids have four sets of chromosomes, et cetera.
Tetraploid daylilies are heralded by some growers as having a number of advantages over diploids. In the tetraploid:
- Flowers tend to be larger.
- Colors of the flower tend to be more intense.
- Scapes tend to be sturdier and stronger.
- Substance of both flower and foliage tend to be heavier.
- Vegetative vigor in leaf, stem, and flower tend to be greater.
- Breeding possibilities tend to be greater because of an increased number of chromosomes
Diploid daylilies continue to charm growers with their exquisite flower form, grace, and color.
- Good pink daylilies are still more prevalent in the diploid ranks.
- Spider and double daylilies are still more prevalent in the diploid ranks.
- Diploid daylilies are easier to cross than tetraploids.
- Many diploid daylilies have been converted to tetraploids, thus advancing the tetraploid lines.
- There are more diploids than tetraploids.
To find the answer to this question, you must know yourself and your reason for growing daylilies. New gardeners tend to focus exclusively on the daylily bloom. With experience comes discretion. Tastes develop and garden requirements surface. Here are some questions you should ask yourself before making a daylily purchase.
- Is the flower sunfast or does it fade in the hot sun?
- Does the cultivar rebloom?
- Does the cultivar exhibit extended blooming habits, or does it finish blooming by early spring?
- Are the scapes low, medium, or tall?
- What about branching?
- Is this my kind of flower?
When purchasing a daylily, consider foliage, vigor and stamina, scapes, branching and buds, and flower substance.
Variation in foliage is important for contrast in color and texture in the total garden picture. Consider the following:
- Foliage is best judged when you are not unduly influenced by the beauty of flower.
- Foliage must have an attractive appearance.
- Foliage should be of a type that is compatible with your climate.
Vigor and Stamina
As to vigor and stamina, the daylily plant should:
- Have the ability to grow and multiply under good conditions without being invasive of adjacent areas by underground rhizomes.
- Establish quickly, thrive, and grow stronger each year.
- Be easy to transplant.
- Not be susceptible to crown rot or spring sickness.
Scapes should have the following qualities:
- The scape must have adequate strength to support the buds and flowers (i.e., you should not have to stake the scape because of wind, rain, or directional light).
- The height of the scape and the size of the flower should be in good proportion to the thickness of the scape.
Branching and Buds
When evaluating branching and buds on daylilies, remember the following:
- The scape should branch so that the buds are not all at the top of the scape.
- Flowers should not open all together or be poorly spaced.
- Branches should be wide apart to allow buds to develop normally without touching and hampering the opening of the fully developed flower.
- Branching and bud count should not be so sparse that flowering ends after a few days.
Good balance means that the overall daylily plant has a pleasing relationship between the foliage and the placement of branches, buds, and flowers. Remember:
- Short foliage and tall scapes with scant high branching often appear poorly balanced.
- Emphasis should be placed on how the scape relates to the rest of the plant, regardless of height.
Flower substance is very important when selecting your daylily. Consider the following:
- Flower tissue should not be thin, and should not wilt, brown, or melt at the edges.
- If the flower fades during the day, substance should be retained reasonably well.
- A flower that opens early in the morning should remain presentable in the evening.
Color has a strong emotional appeal. Consider the following:
- Most people find merit in colors that are clear, bright, soft, vibrant, distinctive, and pleasingly blended. Well-defined markings can add much to the beauty of a flower.
- Murky, dingy, streaked, dull, and faded colors can seldom be considered an asset. Irregular markings are usually considered a flaw, but a few hybridizers are working with spots and streaks and getting some interesting results.
- Like many things, some colors and patterns are currently popular, and something new is always being looked for and pursued. For instance, getting bands of color within eyes or green on petal edges are currently areas of interest.
Flower form, along with color, sets one flower apart from another.
- Many variations in form are favored equally by many daylily collectors; a particular form is favored by others.
- Malformed flowers, dissimilarity of segment shape (except in informal types), and lack of uniformity in placement of flower segments are undesirable aspects of form.
Texture refers to the surface quality of the flower. Consider the following:
- Texture varies from cultivar to cultivar – from the very smooth satiny waxy finish to velvety, creped, pebbled, diamond-dusted, and glistening – to name a few.
- Decide whether flower quality suffers by its texture or is enhanced and beautified by it.
Beauty and Distinction
Beauty and distinction are two essential factors for any worthwhile daylily.
- Many daylilies are being sold that do not possess that special quality called beauty.
- The old saying is true; beauty is in the eye of the beholder.
When buying a new daylily, ask these questions about distinction:
- Has the daylily that special quality that sets it apart from others of a similar kind?
- Is the color, pattern, or special blending of colors different or rare?
- Is the form and texture unique, different, and beguiling; is it something special?
- Does the daylily have the qualities to make it a star in your garden?
Daylilies can be obtained from commercial sources, friends, and society auctions.
Many commercial nurseries and individual daylily growers sell daylilies. Consider the following recommendations:
- Visit nurseries and AHS Display Gardens in your area during the daylily bloom season and see which cultivars appeal to you and which ones grow well locally.
- Annually, the American Hemerocallis Society publishes an Available Source List of daylily growers in the spring issue of the Daylily Journal.
- Many commercial daylily growers listed in the Available Source List offer color brochures listing their daylilies. Many mail their brochures free to members of the American Hemerocallis Society.
- A number of commercial daylily growers now have WWW Home Pages on the Internet.
Society Sales and Auctions
Local and regional daylily societies often hold plant sales and auctions. Auctions are held at meetings or by mail. There is even an auction at each AHS National Convention.
Friends – Because daylilies usually multiply fast and need to be divided periodically, daylily fanciers often share some of their increase with new growers.
Daylily prices range from as low as $3 to as much as $500 for a single plant.
- Do not be scared off by the high price as there are thousands of excellent daylilies in the $3 to $10 price range.
- Only the newest daylilies or significant advances in breeding bring prices of $100 to $300.
- Some recent tetraploid conversions in very limited supply demand the highest prices.
- New growers should venture cautiously into high-price expenditures that might bring disappointment because of high expectations based on high price.
In the North, spring planting is normally preferred. Fall planting in colder climates can prove fatal for daylilies because they often do not have adequate time to form new roots and to begin to anchor themselves before winter comes. Experienced gardeners, however, can plant in the fall provided they:
- Know the hardiness of the plants
- Take some preventative measures such as mulching.
- Learn the time of the year after which it is not safe to plant in their location
In the far South, early spring or very late fall are the most desirable planting times. Please be aware that daylilies planted in July, August, or September when temperatures and humidity are extremely high (i.e., over 90°), face a high probability of rotting.
You need to consider four things in determining where to plant your daylilies:
Sun or Shade
Most daylilies do best in full sun. They will tolerate part-shade conditions, but require a minimum of six hours of direct sun per day.
- Light yellow cultivars, many shades of pink, and delicate pastels need full sun to bring out their lovely colorings.
- Many red and purple cultivars benefit from partial shade in the hottest part of the day because dark colors absorb heat and do not withstand the sun as well as lighter colors.
Type of Soil
Like most plants, daylilies show maximum performance in soils with good aeration, fertility and microbial activity. The ideal soil holds sufficient moisture to sustain the plants, yet is at the same time well-drained. These characteristics can be improved in soils that have too much sand or clay by amending with compost.
For maximum performance, daylilies should be planted in well-drained soil. In some regions raised beds may be beneficial where drainage is a problem. However raised beds should be approached with caution in cold winter regions as being elevated can make the plants more vulnerable to temperature extremes and fluctuations. Note also that raised beds generally require more irrigation during the summer.
Compatibility with Other Plants
Daylilies may not do well near or under trees that compete for moisture and nutrients. They are often reported to do well under pine trees, however, and each situation should be assessed individually. Plants that must compete with tree roots often do better if supplied with extra waterings.
When you receive your new daylilies, use the following technique for planting them.
All Plants Are Received
New daylily plants received bare-root by mail may be “parked” in damp sand or other suitable media until they can be planted. Many daylily enthusiasts like to soak the roots for a few hours or overnight in a bucket of water, however others do not agree with this practice. Some gardeners also include a weak fertilizer in the soaking water, but this isn’t necessary and, if too strong a solution, may actually be detrimental.
Make sure that your daylilies are clean and healthy before planting them.
Prepare the Soil
The soil where you intend to plant your daylilies should be worked into a good loose condition to a depth of at least 1 foot.
- Dig a hole larger than the root mass.
- Make a mound in the center of the hole.
- Set the plant in place with the roots spread on all sides of the mound.
- New plants should be planted about as deep as they grew originally. The original depth can be determined easily by the band of white at the base of the foliage which indicates the part of the plant which was underground.
- Do not set the crown (i.e., the point where foliage and roots join) more than 1 inch below the surface of the soil.
- Work the soil around and between the roots as you cover the plant.
- Firm the soil and water well.
- Make sure that there are no air pockets; this can cause the plant to grow poorly.
- When all the water has soaked in, finish filling in the soil, leaving a slight depression around the plant.
Daylilies should be spaced no less than 18 to 24 inches apart on each side.
Label each of your daylilies with some type of permanent marker so as to identify them. A plant loses much of its value when its identification is lost.
The wise daylily gardener will apply a proper cultural program which includes watering, fertilizing, mulching, possibly spraying, grooming, controlling weeds, and sanitation.
Water is essential for good daylily performance.
- Water, supplied in sufficient amounts, almost certainly increases the number and size of daylily blooms.
- For daylilies, watering is most important in spring when the plants are making scapes and buds, and in the summer during the bloom season.
- Daylilies benefit more from deep watering, which reaches 8 to 10 inches into the soil, than from a succession of brief, surface waterings.
- Caution 1: Overhead watering during the heat of the day will cause any open blooms to spot and/or wilt.
- Caution 2: Watering in the evening can also cause spots on the next day’s blooms.
- Caution 3: Be careful not to over water.
Daylilies grow in a wide range of soils and conditions.
- To determine the nutrient needs of your soil, take a soil sample and have it analyzed. Contact your local county agricultural agent for instructions.
- Daylilies can do well over a relatively wide soil pH range and adjustment of pH need only be considered if the plants appear to be doing poorly. A soil test as recommended above should always be conducted before amending with sulfur or lime.
- In the average home garden, a single fertilizer application in the spring is usually sufficient, although even that may not be necessary every year.
- In extremely poor soils or on light or sandy soils which tend to leach badly, more frequent application may be required. Consult with your local agriculture office for recommendations suitable to your soil and climate.
Mulching, although not essential in every area, generally does contribute to better daylilies by improving the soil and helping retain moisture.
Keep your garden neat and tidy.
- Many gardeners remove the day’s blooms at the end of the day to give their gardens a pristine appearance.
- If you hybridize, expect to leave the pollinated blooms on the plants until the blossom sheds and the tiny seed pod is formed.
The most effective weed control measures for the home garden are mulching and hoeing.
Proper sanitation measures lead to healthier daylilies.
- In the spring, dead foliage and debris should be cleared away from around your daylilies.
- During the growing season, damaged or diseased foliage should be removed.
- At the end of the bloom season, cut off the bloom scapes to within a few inches of the ground unless you are hybridizing.
Daylilies do have some pests, but many do only minor damage. Some diseases also affect daylilies, they too are listed below.
Daylilies have their own specific aphid which feeds only on daylilies.
- Aphids are most active in cool weather – spring and fall in temperate zones, and all winter long in the subtropics.
- Controlling daylily aphids is not as easy as with other kinds of aphids, which are usually vulnerable to such soft controls as soaps.
- In order to reach daylily aphids inside the fans, a pesticide with at least a mildly systemic action is needed.
- Do not use the pesticide Kelthane, which is known to harm daylilies.
Spider mites are among the most common daylily pests.
- Spider mites are most active in hot, dry weather.
- You can get some control of spider mites just by hosing them off as needed.
- Again, do not use the pesticide Kelthane; it is known to harm daylilies.
Several species of thrips are known to infest daylilies.
- Control thrips by starting early in the growing season with a pesticide having either a systemic or long residual action.
- To repeat, do not use the pesticide Kelthane.
Slugs and Snails
Slugs and snails feed on the young, tender tissues, causing ragged edges and holes.
- They feed at night and hide during the day in cool, moist places, such as in mulch, under rocks and bricks, and in dead foliage.
- Sanitation helps to control slugs and snails. Otherwise, control requires using pesticides which are targeted specifically at these pests.
Hemerocallis gall midge
- A small fly – Contarinia quinquenotata
- Known in Europe since the 1800’s, first identified in North America in 2001
- Eggs are laid on developing daylily flower buds causing rotting and distortion
- Pick off and destroy affected buds as soon as noticed
- Purchase bare-root instead of in pots, and remove scapes on new plants if present
- A small fly – Ophiomyia kwansonis
- First reported in North America in 2006
- Larvae create meandering whitish lines in daylily leaves
- Carefully inspect new plants for mines, removing and destroying affected leaves
There are other pests that attack daylilies.
- Other insect pests which have been reported affecting daylilies include cutworms, tarnished plant bugs, cucumber beetles, wasps, Japanese beetles, grasshoppers, and periodical cicadas.
- Bulb mites may be involved in the transmittal of crown rot.
- Deer will sometimes eat daylily flower buds.
More details about each of these pests, including photos, can be found in our Daylily Dictionary.
Most gardeners with a mix of different plants intermingled in their gardens should have little trouble with diseases in daylilies. However, large collections with many plants of a single genus are more likely to encounter problems, especially if those plants are acquired from a large number of different sources.
Environmental conditions and gardening practices inevitably play a role in the development of diseases. Some cultivars may also be less adaptable to different conditions/climates, or less resistant to certain diseases, than are other cultivars.
Older, inexpensive daylily cultivars that remain in wide circulation may be a better starting choice for the inexperienced gardener/daylily enthusiast than more recent introductions not yet tested under a wide range of conditions in many different gardens.
Some daylily diseases and disorders are relatively easy for the home gardener to identify. Others, such as the various forms of crown and root rots, are more difficult and if these become a concern it is advisable to seek a professional laboratory diagnosis. It is important also to know what is normal, for instance a new daylily collector may mistake “summer dormancy” for plant death or disease.
The major daylily diseases and disorders of concern are:
- Caused by a fungus (Puccinia hemerocallidis)
- Orange-yellow powdery spots on leaves and scapes
- Orange-yellow spores mark white tissue when leaves wiped
- Leaves may die back but the plant as a whole should survive
- Some cultivars more susceptible than others, but since this is a new disease in North America this information is currently being collected
- Provide good air circulation and planting distances and minimize overhead watering
- Avoid excessive nitrogen and inadequate potassium nutrition
- Unlikely to persist where all foliage dies back in winter (or roughly Zone 6 and colder) although may be able to do so where there are plants of the alternate host, patrinia
- Appropriate fungicides may be used
Crown and Root Rots
- Plant yellows and may collapse, leaves may pull out easily, affected tissue is often mushy and plant may die. Signs of a fungus may be visible, e.g. “shoestrings” for Armillaria rot, and “mustard seeds” for southern blight (Sclerotium rolfsii), otherwise exact diagnosis requires submission to a diagnostic laboratory
- Foul smell may, or may not, be present
- May involve a combination of factors such as nematodes, bulb mite or other pest damage, fungal and/or bacterial pathogens (disease causing agents), weather conditions, gardening practices, soil aeration and moisture conditions
- Some cultivars may be more susceptible than others
- Of particular concern in warmer climates but may also occur elsewhere
- Ensure adequate soil aeration and drainage
- Avoid or correct areas of poor air circulation
- Avoid too much or too little water and don’t over-estimate water needs in periods of high humidity (check soil moisture before watering)
- Avoid over-fertilizing-Avoid over-amending with high water-retentive organic materials
- Remember that high temperatures increase transplanting stress and try to avoid if possible
- Don’t plant too deep
- Let wounds from dividing air-dry in the shade before re-planting
- Remember that plants in pots are subject to more extreme root/crown temperatures (and therefore stress) than those in the ground
- Treatment differs according to causative agent/s so get laboratory diagnosis of persistent rot problem
- Caused by a fungus (Aureobasidum microstictum)
- Brown spots, yellow streaking, and die-back of foliage but not death of plant
- May require injury such as pest or frost damage in order to infect
- Appropriate fungicides may help
- Foliage is twisted, bending, stunted and discolored on some fans in early spring
- Affected fans may, or may not, recover and bloom normally that season
- Exact cause is unknown
- Probably not a disease
- Not caused by cold damage following shoot emergence
- May involve a combination of contributing factors possibly including, but not necessarily limited to, bulb mites and the leaf streak fungus.
More details about each of these diseases, including photos, can be found in our Daylily Dictionary.
View the complete list of publications available from the American Hemerocallis Society (AHS), available on the AHS Portal here. Publications such as The Daylily Journal and the new Landscaping With Daylilies offer more detailed information about daylilies.
In addition, there is a vast body of knowledge available about daylilies.
View Daylilies in Garden Settings
The best and most natural and pleasant way for a beginner, or anyone, to learn about daylilies is by looking at them.
- The Daylily Journal each spring publishes a list of approved American Hemerocallis Society Display Gardens.
- There are now more than 150 of these AHS Display Gardens across the United States where you can view modern daylilies from a variety of hybridizers.
- And, there are thousands of other commercial and private gardens in the United States and around the world with representative collections of daylilies.
Join the American Hemerocallis Society
Join the AHS and learn more about daylilies.
- Receive quarterly the Daylily Journal and view color photographs and read timely articles about daylilies.
- Read the AHS publications which provide much information about daylilies.
Join a Local Daylily Group
Determine which AHS Region you live in and join a local daylily group.
- Local daylily groups hold informative meetings throughout the year and most hold daylily shows and sales and publish newsletters.
- Each Region holds an annual Regional Meeting and publishes a newsletter.
- From meetings and personal contacts at the local and regional level and from reading local newsletters, you can gain valuable knowledge about daylilies.
View Award-Winning Daylilies
Each year the American Hemerocallis Society presents awards to the best daylilies in a number of categories.
- The annual award winners are presented in the Winter issue of the Daylily Journal.
- You can view the Current and Previous Winners on this AHS WWW site.
- Also listed in the winter issue of the Daylily Journal are the Stout Silver Medal winner, Award of Merit winners, Honorable Mention winners, and the Specialty Award winners. The Junior Citation winners are listed in the Spring Daylily Journal.
- The Award of Merit winners are proven and well-tested, dependable cultivars that grow in many parts of the country. They must receive votes from eight of the Society’s fifteen regions and be among the top twelve vote-getters in that year’s balloting.
- The Honorable Mention winners are newer promising daylilies. They must have grown and proven well in at least four AHS regions and received a minimum of 20 judges’ votes.
- The Junior Citation winners focus attention on new and unregistered daylily cultivars.
Learn About the Most Popular Daylilies
Each year at the regional level, the AHS conducts a popularity poll among its members.
- The spring issue of the Daylily Journal lists fifteen favorites from each region.
- Regional newsletters may carry more of their own favorites.
- You can view the Recent Regional Poll results on this AHS Web site.
Visit Your Public Library
Most public libraries have books about gardening and specifically about daylilies.
- Your local telephone book lists public libraries.
- You can view a list of available Daylily Publications on our Member’s Portal site.
Surf the Information Highway
The Internet provides a vast amount of information about daylilies.
- If you are an AHS member, join the E-mail Robin where you can instantly discuss daylily issues with daylily enthusiasts from around the world by way of the Internet.
- Connect to the various Internet Search Engines and search for daylilies or any other gardening subject.