Daylilies are hardy perennial plants from the genus Hemerocallis. They are not true lily plants; the name is because each bud will open and bloom for one day. The plants grow well in full sun with a pH that is approximately 6.5 to 7. The many buds on each daylily plant provide heavy blooming during the midsummer. Each plant will bloom 30 to 40 days per growing season.
Work compost or organic matter into the soil with a shovel. Dig a hole that is slightly larger than the root mass on the daylily plant. Set the plant in the hole, making sure the crown is no more than 1 inch below the ground. Fill the hole with dirt and lightly pack in place. Allow 18 to 24 inches between each plant to prevent overcrowding.
Water daylily plants immediately after planting. Continue to water the plants weekly until the roots are established, approximately six to eight weeks. Water the plants throughout the summer when rainfall is less than 1 inch per week.
Mulch daylily flower beds each spring with compost, and apply a low-nitrogen fertilizer such as 5-10-5 and water well to promote absorption. Apply a second dose of low-nitrogen fertilizer in early fall.
Each spring, remove dead and damaged foliage that forms around the lower stems at ground level. Remove dead blooms and any seed heads that are present after flowering. Cut back foliage throughout the season as it dies off.
Divide daylily plants when they appear overgrown or crowded, every three to four years. Divide plants in early spring or after flowering is complete. Dig the entire plant and root structure out of the ground with a shovel. Remove dirt from the root clump by shaking the plant to ease in separation. Separate each individual plant section that is in the shape of a fan, making sure to separate roots also.
Monitor plants for pest infestation from thrips, aphids or spider mites. Apply insecticide in spring to control thrip infestation. Spray insecticidal soap to control aphids and spider mites.