Mulching is useful in conserving water and controlling weeds. A third to one half more nitrogen should be added to offset consumption by decomposing mulch. Add lime if needed to raise the soil pH to 5.5 to 6.5. Daylilies are voracious feeders when they are actively growing, and special care should be taken to see that the fertility and moisture levels are sufficient prior to bloom time. Although daylilies are not bothered by many insects and diseases, some pests may cause problems.
Mites can cause injury when plants are in full sun and get dried out.
Thrips and aphids may damage flowers, especially the darker colored cultivars. These can be controlled by timely spraying, using pesticides available at garden supply stores according to label directions. Care should be taken to see that plants are well watered and air temperatures are between 50 and 80 degrees F prior to applications of chemicals. Fungus diseases are not very prevalent on daylilies, but those that may occur can be prevented with fungicides also available at garden supply stores. The roots should be placed in moist peat moss or sand.