Daylilies — Hemerocallis spp. — are desirable for their hardy nature and wide array of colors and patterns. The flowers of daylilies bloom for just one day, opening in the morning and fading as dusk draws near. Because daylilies put out a flower each morning, they look as if they are in continual bloom. Ever-flowering daylilies (often called "everblooming" or "reblooming") were bred to produce flowers that bloom from spring through fall.
Daylilies can be planted as soon as the soil is warm and soft enough to be worked. If the soil is very poor, till in a couple of inches of organic mulch. Dig a hole just large enough to easily accommodate the roots without bending them. Plant each daylily so that the area where the plant meets the roots is about an inch below the soil’s surface. Water thoroughly after planting.
Ever-flowering daylilies are very hardy. They thrive in locations that are exposed to full sunlight, and in soil that is moderately nutrient-rich and well-draining. To encourage reblooming, remove the spent flowers, as well as the seed pods. Dig up and divide (simply put apart, or cut with a shovel) the clump of tubers every three years to prevent the flowers from spreading too rapidly and thinning out in the middle.
‘Stella de Oro’ was the first successful ever-flowering variety bred. According to the Missouri Botanical Garden website, it remains the most commonly cultivated daylily. Compact, durable and a vigorous bloomer, this variety features bright gold, trumpet-shaped flowers. ‘Rosy Returns’ is related to ‘Stella de Oro’ and is similar in form, but with pink flowers. ‘Everblooming Doll’ features pale-yellow flowers and blooms from spring to fall.
Although daylilies will adapt to most environmental conditions, including drought, these flowers will not bloom well if the soil is too rich. Too many nutrients will promote foliage growth rather than flower growth. In addition, standing water can cause the bulbs to rot. Insect pests and diseases are not usually a problem with these flowers.