Divide daylilies to keep them blooming

Q. How do I divide Stella de' Oro daylily plants? Should I also remove seed pods from them?

A. Daylilies are one of the most popular perennial plants grown in the United States. They are tough, strong multipliers, long-lived and available in a wide array of flower colors. There are literally thousands of daylily cultivars that display their glory from early July until fall.

The botanical name for daylilies is Hemerocallis, which comes from the Greek meaning "beautiful for a day." While the blooms generally last for only a day, some varieties can last a bit longer. Despite the fact that each flower is short lived, multiple blooms on the stalks keep this perennial in bloom for two to four weeks.

Tall daylily varieties are appropriate for the backs and middles of borders. Dwarf types are suitable for rock gardens or border fronts. They are best planted in average, well-drained soil where they receive at least a half-day of sun. To promote continued blooming, either remove the spent flowers immediately, or cut off the daylily seed pods that have formed as soon as possible.

Once established, daylilies spread quickly to form dense clumps that you should divide every three to four years. You will know it is time to divide them when their blooms become increasingly sparse. Divide clumps in spring or fall by digging them up and separating them into sections (each with two to three stems or fans of leaves and with its own roots attached). If dividing in fall, cut the grasslike foliage back to about 6 inches. Replant the portions as you would a bare root plant, making sure that the crown is at least 1 inch below the ground line. Watering the plants thoroughly afterward helps to ensure successful establishment. Consider mulching the plants for protection during winter time.

• Ask a Master Gardener is written by Anne Gachuhi, University of Illinois Extension Horticulture Educator and Extension Master Gardeners Mary Moisand and Mary Boldan. Send questions to Ask a Master Gardener, P.O. Box 280, Arlington Heights, IL 60006, via e-mail to agachuhi@uiuc.edu with "Ask a MG" in the subject heading or leave a message at Friendship Park Conservatory, (847) 298-3502 or at the Rolling Meadows Master Gardener office at (847) 818-2901. Include your name and address on all questions. For more gardening information, visit http://cook.extension.uiuc.edu and click on Urban Horticulture.