Daylilies combine stunning, long-lasting floral displays with rugged resilience, so it’s little wonder daylily is America’s most popular flowering perennial, said University of Missouri Extension horticulturist David Trinklein.

June is the month most daylily cultivars are at their best and an ideal time to enjoy their colorful, carefree flowers, Trinklein said.

Daylily is not a true lily; it belongs to the genus Hemerocallis, derived from the Greek words hemera (day) and kalos (beautiful). This refers to the fact that the showy flowers of this plant rarely last more than 24 hours.

One of the first written records of daylily dates to 2697 B.C. and indicates the ancient Chinese used it as food and medicine. Herbals and pharmacopeias of that era referred to the daylily as “xuancao,” which means “the herb that helps forget sadness.” Along with other benefits, it was thought to relieve anxiety and soothe difficult emotions.

Settlers brought daylilies to the New World; by the late 1800s, many species could be found in American gardens. But it was the work of geneticist and plant breeder Arlow B. Stout that started daylily on the path to the popularity it enjoys today.

His work not only resulted in the development of hybrid daylily cultivars but also produced an understanding of the genetics of the genus Hemerocallis. Stout’s legacy is perpetuated by the American Hemerocallis Society’s Stout Medal, the highest and most prestigious honor a daylily cultivar can receive.

Stout’s work encouraged both professional and amateur plant breeders to hybridize daylily. Their efforts have resulted in more than 90,000 daylily cultivars registered by the American Hemerocallis Society, with an average of 200 new registration requests submitted monthly.

Daylilies thrive across a wide range of climates and soils, gracefully shrugging off harsh conditions like drought, heat and pests with minimal maintenance. Although daylilies are famous for surviving neglect, proper care yields far more vibrant and attractive blooms. They are true sun lovers, needing six to eight hours of direct sunlight daily, though a little afternoon shade helps keep the flowers looking fresh longer.

While daylilies tolerate a wide array of soil types, they prefer a well-drained, medium-heavy garden loam. You can improve soil of any texture by incorporating liberal amounts of well-decomposed organic matter before planting.

Additional fertilizer should be applied sparingly since too much nitrogen can harm the plants. Daylilies growing in very rich soil require little (if any) additional fertilizer. In average garden loams, a complete fertilizer such as 5-10-5 in the spring of the year when new growth starts is usually adequate. Extremely poor soils or soils that leach easily might warrant a follow-up application. Maintain soil pH around 6.5 for optimum nutrient availability.

Daylilies thrive with about an inch of water per week, optimally delivered through a deep, morning soak at the base of the plant. Surface application is preferred, since overhead watering during bloom can spot the delicate petals. While mature daylilies are reasonably drought-tolerant, newly planted ones need consistent moisture until established. All types of daylilies benefit from supplemental watering during drought.

Daylilies occasionally fall victim to fungal diseases like leaf streak and rust, as well as pests like spider mites and thrips. Good garden hygiene, proper soil drainage and proper cultivar selection are the best defenses.

Weed control in daylilies is best accomplished with an integrated approach. The most practical strategy for home gardeners is to apply a 2- to 4-inch layer of organic mulch such as pine bark, pine straw or shredded hardwood coupled with routine hand-pulling or shallow hoeing. To prevent weed seeds from germinating, apply a safe pre-emergent herbicide, like those containing trifluralin, provided the soil remains undisturbed after application.

Daylilies require periodic division for best garden performance. How often you should divide them depends largely on cultivar and growing conditions. Remontant cultivars known for their reblooming ability, such as ‘Stella de Oro,’ should be divided relatively frequently. This helps to force new growth, which is important for reblooming. You can divide or plant daylilies any time the ground is not frozen, but late August through September is preferred.

By Linda Geist, University of Missouri Extension