When to plant Daylilies can be planted very successfully at any time the ground can be worked --- spring, summer or fall. Fall planted Daylilies should be mulched to prevent winter frost heaving.Where to plant
Daylilies are sunloving flowers but they also bloom rather well in partial shade. Six or more hours of direct sunshine is preferred. Despite this preference, we are occasionally surprised to find colorful Daylily blooms under the constant shade of tall trees. Wherever some shade is present, the Daylily flowers will face away from it toward open sky. Site conditions to avoid, or to improve, are low wet spots where water collects in rainy spells, and high dry spots over ledges where the soil is shallow.
Loose loamy soil is excellent. Sand, gravel and clay are very poor. Mediocre soils will be improved by adding compost, rotted leaves or wood chips, old manure, or almost any other organic material.
In a mixed perennial flower border allow a circle of 16-18 inches in diameter if the Daylily will be divided and replanted in 3-5 years. If you expect to leave the Daylily clump intact for 10-15 years, it will need a 24-30 inch space. The same applies to a Daylily flower border. In a landscape setting, such as a bank to be covered with Daylilies, space the Daylily plants in a triangular pattern with each plant 24 inches from its neighbors. 100 square feet of bank will then require 30 Daylily plants. (Multiply square footage by 0.304.) As an edging along a walk, space the Daylily plants 12-18 inches apart in a single line.
One to four inches of mulch will retain soil moisture and inhibit weed growth among the Daylily plants. Leaves, hay, woodchips and grass clippings are suitable, but they withdraw some of the soil nitrogen during their own slow decomposition. You may wish to add some fertilizer, especially with freshly cut woodchips. Where the ground normally freezes in winter, fall-planted Daylilies should be mulched heavily the first year to prevent them from being heaved out of the ground.
An organic composty soil is seldom deficient in plant nutrients. To maintain excellent Daylily growth, add any slow release, composted organic matter such as horse, sheep, or cow manure, or your own compost, in either spring or fall.
Dividing This may be helpful after 8 to 15 years, or it may not be necessary at all.
For best performance, Daylilies like a lot of rain, or evening watering, just before and during flowering. Flowers will be larger and more numerous, prolonging the Daylily bloom season.