Daylilies
Daylilies (Hemerocallis sp.) are a common sight in many of today's landscapes. They are easy to grow, have few insect and disease problems and are available in many colors. In addition, they tolerate heat, drought, salt, compacted soil and various pH's. A daylily is available for almost any landscape condition.
Anne Streich, Extension Horticulturist, Outreach Programs
Don Steinegger, Extension Horticulturist
Plant Characteristics
Daylily leaves are long, narrow and arch from a central division back toward the ground. This central division is also called a fan. Flowers rise above the foliage on a scape, and, as the name implies, last for only a day. However, the 30 to 50 blooms per fan allow daylilies ot bloom over several weeks. Established daylily clumps often have several fans and can produce 200 to 400 flowers in a season.Cultivar (variety) heights range from six inches to more than four feet. With this variation in height, daylilies can be used in both large and small landscape sites. Smaller cultivars can be used as edgers and foreground plants, while the larger daylily cultivars can be used in background plantings, as accents, or in front of tall hardscape elements such as fences and decks. Daylilies also work well in mixed borders and beds. They maintain their flowering, growth and space when planted with more aggressive plants.
Flowers range from less than two inches to more than eight inches across and have several different shapes. Shapes include:
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Numerous daylily colors and color combinations are available. The only unavailable colors are pure blue pure white. Careful consideration of color and color combinations can create an aesthetically pleasing landscape. For example, when using daylilies in bright light, choose bright colors because pastels will bleach out and lose their visual effect.
Daylily color is classified as the basic flower color, which refers to the outer portion of the daylily; the throat color, which erfers to the interior area of the flower; and the stamen color, which refers to the male reproductive organs in the middle of the flower. The following terms describe color patterns in daylilies: self, where all flower petals and sepals are the same color but the stamens and throat may be different colors; blend, where flower segments are a blend of two or more colors and the stamens and throat may be different colors; polychrome, where flower segments have an intermingling of three or more colors and the stamens and throat may be different colors; bitone, where petals and sepals have the same basic color but differ in shade or intensity; bicolor, where petals and sepals are different colors; eyed, where the flower has an area of different color or shade located between the throat and tips of the flower segments; and edged, where edges of the flower segments are either darker or lighter than the segment color.
More than 35,000 named cultivars are registered with the American Hemerocallis Society. This NebGuide doesn't include a list of suggested cultivars because they are continually released. Local garden stores and nurseries generally carry the most popular cultivars for their area and can offer recommendations. Unusual cultivars must be ordered through catalogs or purchased at specialty nurseries and can be very expensive.
Daylilies may be purchased as either bare-root or container specimens. Their root systems range from fibrous to common fleshy types. Some consist of rhizomes or stolons that spread quickly throughout the soil. These aggressive types are ideal for steep areas that are difficult to mow and need a quick groundcover to help control soil erosion.
Daylily Type
Most daylilies are herbaceous, but evergreen and semi-evergreen daylily cultivars are available. Herbaceous daylilies, also called dormant daylilies, die back as winter approaches. A resting bud, from which new leaves will emerge in the spring, is formed in the crown of the plant. Evergreen daylilies retain their green foliage all year, and in southern climates continue to grow new leaves throughout the year. Semi-evergreen daylilies may retain their color throughout the year or, in some locations, may die back during the winter. Evergreen and semi-evergreen daylilies aren't commonly grown in Nebraska.Cold tolerance isn't related to the type of daylily. Hardy evergreens and tender dormants exist, but tender evergreens and hardy dormants are more common. Dominant and semi-evergreen daylilies require a cold period. Without this cold period, they will gradually decline, reduce flowering and may die.
Breeding efforts have resulted in new daylily cultivars that are tetraploid instead of the standard diploid. Tetraploid daylilies have twice as many chromosomes as the diploids. The tetraploid daylilies have larger flowers, more intense but fewer colors, and sturdier scapes that better withstand wind. However, the tetraploid size may be overwhelming in small gardens. Many people still prefer the diploids because of their fine form, grace and diverse colors.
Bloom Type
Reblooming daylilies, those that flower more than once during the season, are available. Some flower in the spring and then rebloom in the fall. Others just have a succession of bloom periods that offer flowers over several months. Weather and location conditions often influence rebloomers. In one location they may be considered a rebloomer, but in another they may just bloom once and are considered a standard daylily. Rebloomers tend to have smaller flowers and may take longer to come into initial bloom.Evening bloomers, daylily cultivars that flower in the evening and remain open until the following day, also are available. Many of these night-blooming plants are fragrant and are ideal for locating along a path or deck where the fragrance can be enjoyed.
Planting and Propagation
Daylilies are very hardy and can be planted almost any time the soil can be worked. They grow best in a well-drained, slightly acidic soil but are able to grow under both dry and wet conditions. In a new flowerbed, poor soil should be amended with six inches of compost and worked in to a depth of 12 to 18 inches. Prior to planting, a soil test will determine if additional nutrients are required. If needed, fertilizer should be incorporated with the compost.Plant daylilies so the crown is level with the soil or no more than one inch below it. The planting hole should be larger than the spread of the root mass. Set the plant on a mound in the middle of the hole and spread the roots out in all directions.
As with many landscape plants, daylilies should be planted in masses to create a bold impact. At minimum, three of a single daylily cultivar should be planted together. A larger number of smaller cultivars may be needed to get a similar impact.
Daylilies perform best in full sun but will tolerate partial shade. They flower best with at least six hours of direct sun daily but light shade during the hottest part of the day will help keep flowers fresh.
Daylilies grown in complete shade will be taller and have fewer blooms.
The best time to divide daylilies is in early spring as new growth emerges or in the fall after flowering is complete. Divisions can be made by digging up the entire plant and gently pulling the fans apart. A spade may be needed to divide plants that have thick stolons or rhizomes. Each division should have two or three fans of leaves with some roots attached. They should be replanted and watered in immediately.
Most daylilies are vigorous growers and need dividing every three to four years. Some may need to be divided more or less frequently, depending on growth rate. Undivided daylilies often will continue to grow and provide a groundcover, but will have fewer blooms.
Daylilies also can be propagated by seed. Seeds require six weeks of moist chilling before planting and then three to seven weeks at 60-70oF to germinate. Most daylilies propagated by seed will not be identical to their parent.
Culture
Although daylilies are very tough plants that can survive with little nutrient input, a spring application of a fertilizer such as a 5-10-5 may help provide nutrients for plant growth and increase flowering. Excess nitrogen will increase foliage growth at the expense of flowering. Deadheading or removing spent flowers will promote longer flowering. Unless collecting seeds for planting, also remove seedpods so energy will go into the blooms the following year.Daylilies will continue to flower even during the heat of summer when other flowers may slow down. However, they will benefit from an occasional watering during the growing season, especially during extended dry periods. Daylilies also respond favorably to additional moisture before bloom.
Perennial grasses that become established in daylily clumps can be difficult to eradicate. A pre-emergence herbicide containing trifluralin or pendamethalin will help control some broadleaf and grassy weeds in daylily beds. For current herbicide rates and other information, read the herbicide label. Mulching two to three inches deep also will help eliminate some weed problems.
