ID

426-030

Authors as Published

Lynne Hightower, Undergraduate, Department of Horticulture; Diane Relf, Extension Specialist, Consumer Horticulture; and Kate Dobbs, Information Officer, Consumer Horticulture; Virginia Tech.

Table of Contents

Introduction
Cultural Requirements
Categories
Propagation

  

Daylilies are good plants for the beginning gardener because they are relatively maintenance free. Daylilies are not true lilies (genus Lilium). They belong to the genus Hemerocallis, from the Greek words meaning "day" and "beauty" or "beautiful for a day." This is appropriate because each blossom typically lasts no more than a day. Each plant produces an abundance of buds, however, so the total blooming time of a well-established clump may be 30 to 40 days.

Daylilies are grown both for their foliage that makes an excellent ground cover and attractive flowers that vary in form and color. Petal shapes available are wide, slightly recurved, overlapping, crinkled, frilled, and ruffled. The general flower shapes vary from trumpet- and cup-like to those resembling bells. Daylilies occur in a wide assortment of colors including white, yellow, orange, pink, red, and purple with a range within each color category. There are midget, dwarf, intermediate, and tall forms, thus heights range from one to four feet.

The flowers last for a day, but are continuously being replaced the next day for as long as six weeks. By selecting early, mid-, and late-season varieties, it is possible to extend the flowering season from May until September.

Features that make daylilies a favorite to grow are dependability as perennials, hardiness, and the fact that they are prolific bloomers relatively free of pests. They are tolerant of drought and flooding; immune to heat stress; tolerant of most soils, full sun, or light shade; and they do not require fertilizer. They can be grown in most areas of the country, make excellent cut flowers, and have edible flower heads. The foliage also is quite attractive, offering an interesting textural contrast to other fine-foliaged perennials.

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Cultural Requirements

Light : Daylilies grow best in direct sun or light shade. They perform best with six hours or more of full sun daily.

Soil: A slightly acidic (pH 6 to 6.5) garden loam with good drainage and ample humus is preferred.

Planting: Planting may be done between April and September. Spacing generally is two to three feet between each plant (15 to 18 inches between miniatures).

Water: Keep plants evenly moist, but not constantly wet. Water should be thoroughly applied following planting until the plants are established. Consistent watering during the flowering period encourages high-quality flowers. A drip-irrigation system is ideal for daylilies.

Fertilizer: Daylilies usually grow well without fertilizer applications. However, if a soil test indicates the need for fertilizer, apply it in early spring. Avoid fertilizers containing too much nitrogen because excess nitrogen encourages flowers with extremely tall stems that break easily.

Mulch: Mulch is not necessary, but helps to conserve moisture in the soil and control weeds. When choosing a mulch, consider ease of application, durability, attractiveness, moisture retention, cost, and availability.

Pests: Previously considered relatively free of pests, daylilies now have a major disease problem. Daylily rust, caused by the fungus Puccinia hemerocallidis, was identified on daylilies in southeastern United States in the summer of 2000. In addition to a rapid incubation period, only 2 to 3 days from inoculation, this disease spreads quickly in the nursery or garden. To date, known infections have all been on the daylily foliage and flower scapes, not the tuber. Daylily rust is easily identified by localized, small orange to yellow-orange "blisters" (pustules) that contain orange, dustlike spores. These pustules are located primarily on the underside of leaves. The affected leaves discolor as they dry up. To distinguish between daylily rust and daylily leaf streak (another fungal disease), simply scrape a pustule with your finger. An orange streak of spores is very diagnostic for daylily rust.

Rusts require an alternate host to complete their life cycle. In this case, the alternate host is Golden Valerian (Patrinia sp.), an ornamental perennial plant. Although the alternate host is not required for infection of daylily, you can reduce the disease pressure by not growing daylilies and Golden Valerian in the same landscape. Considerable ongoing research is identifying cultivars resistant to daylily rust, but the sheer number of daylily cultivars available make it imperative that homeowners do their own trials. Cultivars that are listed as resistant are not necessarily immune to infection. They may have fewer lesions compared to susceptible plants. Examine your own cultivars for symptoms of the disease and replace highly susceptible cultivars with more resistant selections. Daylily rust can also be managed with timely, season-long applications of fungicides. Check with your local Virginia Cooperative Extension office for recommendations. However, for sustainable management of this disease in home landscapes, use of disease-resistant cultivars is preferred. It is also unclear if the rust spores can survive Virginia winters. Therefore, it is a good precaution to remove any infected foliage from the garden to reduce the inoculum the following year.

Other pests of daylily include slugs, but they can be prevented by the use of slug bait and removal of dead leaves and old bloom stalks. Aphids, red spider mites and thrips are occasional pests of daylily. For current pest control recommendations, contact your local Virginia Cooperative Extension office. Some varieties are susceptible to "Spring Sickness," which seems to be related to sudden freezes and thaws in northern climates. Selecting hardier varieties can reduce this problem.

Daylily Cultivars with Resistance to Daylily Rust (University of Georgia, 2002)
NAMECOLORHEIGHTBLOOM*
Resistant
Buttered Popcornyellow28"ML
Carolyn Criswellbuff yellow22"E
Chicago Apachescarlet red27"M
Follow Your Heartpale strawberry with shrimp pink blend33"M
Green Flutterruffled canary yellow/green throats20-24"ML
Hush Little Babyrose pink22"ML
Mardi Gras Paradelavender with wine eye24"EM
Prairie Blue Eyeslavender, blue eye zones, green throats28"M
Woodside Rubyruby red34"M
Moderately Resistant
Bertie Ferrisorange20"E
Black Eyed Stellagolden yellow/dark red eye13"E
Daring Deceptionpale lavender pink/black purple edge and eye24"M
Ed Murrayred30"M
Gordon Biggsraspberry red/red eye24"E
Joan Seniornear white25"EM
Nanuqnear white27"ML
Stella de Orogold11"EM
Texas Sunlightgold28"M
*E = very early to early   EM = early to midseason   M = midseason   ML = midseason to late

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Categories

Daylilies are fibrous-rooted, hardy perennials that require a cold-induced period in order to flower the following year. Daylilies can be divided into three categories based on their foliage habits: 1) Dormant types - the plant dies back to the ground following the first hard frost in autumn and grows new foliage in the spring; 2) Semi-evergreen types - the foliage only dies back partially and resumes growth in the spring; and 3)

Evergreen types - the foliage is retained year round. In general, evergreen types can only be grown in the South and dormant types in the North. Virginia is capable of supporting all three categories.

There are also three categories of daylily blooming times: 1) Diurnal types bloom in early morning and last until the evening; 2) Nocturnal types bloom in the late afternoon and stay open until the following morning; and 3) Extended types remain open for as long as 16 hours and bloom at sunrise or late afternoon.

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Propagation

Propagation of daylilies is done primarily by division following flowering, although they will tolerate division throughout the entire growing season. Prior to division, cut the foliage back to one-half its length to ease handling and reduce water loss. If you are going to replant in the same location, replenish the soil before planting with well-rotted compost and a fertilizer high in phosphorus for root development. In the actual division process, it is best to begin by digging around the daylily clump with a spade and gently lifting the clump from the ground. Excess soil should be removed by hand or by spraying the root system with water. At this point, the clump can be divided into sections or "fans." Each fan should be planted in a hole that is 24 to 30 inches wide at a depth so the crown is about 1/2 to 1 inch below the soil level. It helps to make a mound of soil in the center of the hole and plant each fan so its roots are spread at a downward angle in the shape of a tepee. Next, the hole is filled in, and the soil is firmed. Each plant is then watered thoroughly to encourage root growth.

Daylilies should be divided every three to six years. Divide the plants when the clumps become too dense, when there is an obvious decline in the quality and number of flowers, or when you want to introduce them to a new location. However, some varieties may grow well for many years without being divided.

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Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.

Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg.

Publication Date

May 1, 2009