The sheer beauty of daylilies belies their sturdy, rugged, adaptable nature. Practically care-free once established, these long-lived plants will benefit from just a little thoughtful effort to get them going. Plant daylilies in the spring as soon as the ground is free of frost and can be easily worked. The sooner you get them in the ground, the more time they'll have to strengthen and prepare for the winter ahead. Potted and bare-root daylilies are readily available from gardening centers.
Select a fertile, very well-draining location where your daylilies won't have to compete with shrubs and trees for crucial moisture and nutrients. The soil should have a high level of organic content and a pH range of between 6.5 and 7.0. Plant purple and red daylilies where they'll be partially shaded during the hottest part of the day. Those deep colors absorb heat and don't tolerate sun exposure as well as the lighter shades. The subtle color hues of more delicate pinks, yellows and pastels intensify and brighten with full sun.
Soak the roots of bare-root daylilies for three or four hours in a bucket of water in the shade. Cultivate the soil of the planting site to a depth of about 12 to 15 inches. Apply a 2- to 4-inch layer of compost and work it into the soil thoroughly.
Dig a hole about 50 percent larger than the daylily's root mass and make a mound of soil in the middle of it. Set the plant on top of the mound and gently spread the roots over it. Position the lily so that the point where the foliage meets the roots (the crown) won't be planted any deeper than 1/2 to 1 inch below the soil surface. Firm some soil into place around the roots and the mound. Fill the hole the rest of the way with water. Allow it to soak into the soil completely, then fill the hole with soil. Space multiple daylilies 18 to 24 inches apart.
Mulch your daylilies to a depth of 1 or 2 inches with straw or leaf mold. This will go a long way in retaining soil moisture and discouraging weeds.
Feed a complete 5-10-10 fertilizer for blooming plants about a month after planting and once each spring before blooming thereafter. Feed a low-nitrogen 3-12-12 fertilizer in late summer or early fall after blooming has ended every year. Follow the packaging instructions carefully.
Water slowly and thoroughly throughout the growing season. Daylilies should receive an inch of water weekly.
Cut freely for your indoor arrangements throughout the blooming season. Deadhead spent blooms to maintain a tidy appearance. Remove the developing seed pods from your daylily plants after each bloom fades. If you don't, seeds will be produced, and reproduction saps a daylily's resources and takes a serious toll on performance. The result is highly reduced flower production next season.
Prune flower stalks to the ground after daylilies have completed their blooming for the season.
Divide daylily clumps once every three to four years.