Daylilies can be maintained in the same location for several years, and will look more attractive after being established for a period of years. Dividing is recommended if an established clump experiences diminished bloom.
Digging and dividing can be undertaken anytime the plant is active in growth, including during its bloom. Begin by liberally watering the clump. Let dry for a day or two until the soil is moist, but not wet. Dig the entire clump and knock any dirt off the roots. Cut back foliage to a length of 8 or 9 inches. Gently, with either your hands or the aid of a pair of screwdrivers, pry the clump apart and continue to divide the clump into single and double fans. Cut off any damaged roots and replant.