Daylilies are perennial plants, whose name alludes to the flowers which typically last no more than 24 hours (about a day or so). The botanical name, Hemerocallis, means “beauty for a day.” The flowers of most species open in early morning and wither during the following night, possibly replaced by another one on the same flower stalk the next day. The stalks typically have at least a dozen flower buds, so some plants stay in bloom for several weeks. Most daylily plants bloom for 1 through 5 weeks, although some bloom twice in one season. Some varieties will bloom in early spring while others wait until the summer or even autumn. They are not commonly used as cut flowers for formal flower arranging, yet they make good cut flowers otherwise as new flowers continue to open on cut stems over several days.
The daylily plant is often called “the perfect perennial,” due to its brilliant colors, resistance to disease and pest, ability to tolerate drought and frost, ability thrive in many different climate zones, and generally low maintenance. It is a vigorous perennial that lasts for many years in a garden, with very little care and adapts to many different soil and light conditions. By choosing early-, mid-, and late-flowering cultivars, you can have daylily flowers blooming through most of the summer. If you also mix various heights, flower colors, and flower shapes, you can enjoy new and different flowers each day. The shorter, more compact varieties work well planted directly into perennial borders, where their blooms provide a welcome mid-summer boost. In groups of 3 or 5, daylilies are ideal for landscape plantings, especially when paired with ornamental grasses and small shrubs. Daylilies are also the perfect plant for mass plantings along a fence or walkway, where they’ll form a dense, weed-proof display.
Daylilies flower best when planted in full sun (6 hours/day), on moist, yet well-drained soil. In hot climates, dark-colored cultivars should receive some afternoon shade to help them retain their flower color. When planted in the correct location, daylilies will flower for years with little care. Amend the soil with compost before planting. Space plants 12 to 18 inches apart and plant so the crown is about 1 inch below the soil surface. Water well and mulch with bark or straw to conserve moisture and prevent weeds from growing. Although resilient once established, young transplants should be kept free from weeds and well watered the first year. Daylilies do not require fertilization other than a yearly addition of compost. Depending on their growth, a daylily clump will usually become crowded after four to five years and flowering will diminish. In most areas, late summer is the best time to divide daylilies. Dig up individual clumps and put them on a tarp. Use a sharp knife or spade to separate healthy young plants (fans) with strong root systems. Cut back the foliage and replant immediately in compost-amended soil or plant in containers for holding. You’ll have many extra plants from each clump to give away to friends and neighbors. Discard any small or diseased plants. Apply mulch around the plants in fall for winter protection.
Hemerocallis is popular worldwide because of the showy flowers and hardiness of many kinds. There are over 80,000 registered cultivars. Hundreds of cultivars have fragrant flowers, and more scented cultivars are appearing more frequently in northern hybridization programs. Some earlier blooming cultivars rebloom later in the season, particularly if their capsules, in which seeds are developing, are removed. The Tawny Daylily (Hemerocallis fulva), and the sweet-scented Lemon-lily (H. lilioasphodelus; H. flava, old name) were early imports from England to 17th-century American gardens and soon escaped from gardens into natural areas. The introduced Tawny Daylily is now common in many natural areas, and some consider it a wildflower. Its common names include Railroad Daylily, Roadside Daylily, Ditch Lily, Outhouse Lily, Tiger Lily, and Wash-house Lily (although it is not a true lily).
Most kinds of daylilies occur as clumps, each of which has leaves, a crown, flowers, and roots. The long, linear lanceolate leaves are grouped into opposite fans with arching leaves. The crown is the small white portion between the leaves and the roots. Along the flower stalk of some kinds of daylilies, small leafy “proliferations” form at nodes or in bracts. A proliferation forms roots when planted and is often an exact clone of its parent plant. Many kinds of daylilies have thickened roots in which they store food and water.
A normal, single daylily flower has three petals and three sepals, collectively called tepals, each with a midrib in either the same basic color or a different color. The centermost part of the flower, called the throat, usually is of a different color than the more distal areas of the tepals. Each flower usually has six stamens, each with a two-lobed anther.
While the flowers of Hemerocallis citrina are edible and are used in Chinese cuisine, Hemerocallis species are toxic to cats and ingestion may be fatal. Treatment is usually successful if started before renal failure has developed.