Daylilies (Hemerocallis hybrids) are not true lilies, but their wide variety of colors and tough, pest-resistant nature make them favorites in the garden. They are easy to grow, require little care and reblooming varieties provide large, bright flowers for a month or longer.
New, untested cultivars appear every year; look for recommendations from daylily societies.
Daylilies grow well in average soils and do not normally require fertilizer. If your daylily is struggling, first consider other problems. Wet, poorly-draining soil, deeply-planted tubers or severe insect infestations all contribute to poor growth and damaged or non-existent flowers.
Heavily-blooming daylilies appreciate an extra nutrient boost.
If you wish to produce the largest blooms and the healthiest plants, add a light fertilizer. Fertilize daylilies in spring, when new growth appears. Repeat the light feeding in midsummer as the daylily is actively blooming.
University of Rhode Island Extension recommends a low-nitrogen fertilizer with a high ratio of potassium and phosphorous. Too much nitrogen pushes leaf growth over healthy roots or flowers. Slow-release fertilizers ensure a long-lasting, mild growth boost without overfertilization