Daylilies (Hemerocallis spp.) are named for their short-lived blooms, but these perennials can produce flowers for three to four weeks with the right care. Daylilies are hardy in U.S. Department of Agriculture plant hardiness 3 through 9 and grow 6 to 36 inches tall and 18 to 24 inches wide, depending on the variety. Watering daylilies frequently, removing their faded flowers, dividing them when crowded and growing them in full sun encourage prolific flowering.
Continually moist soil promotes flowering in daylilies. These plants are drought-tolerant, but they flower best when they receive 1 inch of water per week, and they need more water when the weather is hot and dry.
Water daylilies thoroughly when their first flower buds appear in spring, and spread a 2-inch-thick layer of shredded leaves or other light mulch over the bare soil between plants. Water the plants again when the soil surface is dry; scrape back some mulch to check if you aren't sure about the soil's condition. Don't water the plants so much that the ground becomes soggy.
Removing Faded Flowers
Taking off faded flowers prevents daylilies from developing seeds, which encourages more blooms. Seedpods behind the faded flowers must be removed to prompt the plants to flower again.
Daylilies produce many flowers on single stems, and usually the flowers last about one day. Every two or three days, pinch off the faded flowers and developing seedpods where they join the stems. When all the flower buds on a stem have bloomed, prune the stem at its base. Sterilize pruning shear blades before and after pruning daylilies by wiping them with a cloth that was dipped in rubbing alcohol.
Poorly performing daylilies may be crowded, and dividing the plants usually increases blooming. Daylilies grow in fan-shaped clumps, and over time these clumps become congested. A sign of crowded plants is few flowers.
Divide daylilies in spring. Push a garden fork deeply into the ground several times around a daylily clump, levering the fork upward each time until the daylily's root ball lifts out of the ground. Using a sharp knife or two garden forks inserted back to back into the clump then pulled apart, divide the clump into three or four sections. Plant the sections 18 to 24 inches apart and at their original growing depths.
Using Full-Sun Sites
Daylilies flower best when planted in a full-sun location. Specimens growing in partially shaded spots grow well, but they flower less. Growing daylilies in areas that receive at least six hours of sunlight daily provides the most flowers, but in warm climates the plants need some light shade during the hottest part of the day.
Remove sources of shade, such as overhanging foliage, or transplant shaded daylilies to a full-sun site. Daylilies also can be replanted in a sunny spot after their clumps are divided in spring.