The daylily (Hemerocallis) remains one of the easiest perennials for the low-maintenance garden. However, failure to bloom is not usually a problem. Specific conditions are occurring if the plant is not readily forming flowers in late spring or summer.
Lack of Sunlight
Dayllilies need lots of direct sunlight.
Daylilies need lots of sunshine. If the plants are not receiving direct sunlight for at least six hours a day, the plants likely will not create any flower stems but remain a clump of strappy foliage.
Stressful Growing Conditions
Daylilies also may fail to flower if they are growing in less-than-favorable growing conditions. Examples include nutrient-poor soil or consistently dry conditions. Pure sand, gravelly soil or compacted clay soil can prevent the daylilies from growing healthfully. Also, if the winter cold was exceptionally brutal and there was no mulch or thick snow cover over the dormant roots, the plants may have endured dieback and are focused more on making food with their leaves than making flowers. A severe disease, like rust, can also weaken plants so that energy is not directed to making flowers.
Lack of Water
Daylilies appreciate moisture in spring as they prepare to form their flowers, but don’t waterlog them.
Daylilies, although drought tolerant, require moist soil in the several weeks before flowering. Their water needs increase as the plant is forming stems and plump, healthy flower buds.
Too Much Fertilizer
Daylilies appreciate fertile soil, but adding fertilizers that are very high in nitrogen (N) promotes leafy growth, not flower production.
If daylilies are planted too deeply, they may rot or simply falter in their health and growth. The fan of roots and tubers should be a few inches below the soil, with the crown (the point where the roots meet the green stem), positioned right at the soil line.
Time of Year
Although daylilies can be deciduous or evergreen in their foliage and appearance, they flower only after some form of a dormancy, usually in a cool to cold winter period. They also flower in spring and summer. Make sure you haven’t come across a daylily plant after it has already flowered and only dried seedpods or shriveled flower stems remain.