When do you cut down daylilies?

Cut down, or prune back, daylilies in the fall, writes gardening expert Marie Iannotti for About.com. Pruning promotes a cleaner area in the spring. Daylilies are hardy in USDA Hardiness Zones 3 through 9 and respond well to a shearing in the fall.

The American Hemocallis Society states that daylilies are native to Asia, and while there are a vast array of colors, there were originally only three colors: red, orange and yellow. Many flowers bloom on each stalk, and some cultivars even have more than one blooming season. Daylilies are named from two Greek words that mean "day" and "beauty," according to the American Hemocallis Society.