They prefer moderate nitrogen and higher rates of phosphorous and potash. Slow-release fertilizers are best for daylilies. Put down fertilizer in the early spring just as new growth commences, and again in midsummer. Make sure that the soil is moist whenever applying fertilizer. Mulch helps to conserve moisture in the soil and control weeds.
Daylilies grow rapidly to form dense clumps.
Division is not essential but may revitalize flowering if the plants have become crowded. Division is the usual way to increase your supply of daylilies. Dividing is usually done following flowering, but plants will tolerate division throughout the entire growing season. Lift the entire clump or cluster out of the soil with a garden fork. Daylilies look best if given some grooming through the year.