Gardeners consider colorful, reliable daylilies so carefree that they may forget the flowers benefit from division every four to five years. Daylilies spread by underground rhizomes, ensuring that the tiny stalk you plant today will grow into a huge clump of dozens of flowers within a few years. While it's possible to ignore the thinning chore altogether, if you divide and transplant daylilies regularly, you'll not only create new plants which cost nothing, but also achieve more vigorously blooming plants.
Look over your daylily plants to determine whether they need dividing. Telltale signs include overcrowding, diminished flowering and thin or brown foliage.
Wait until late summer or early fall, when the daylily stops flowering. If you can't wait until then, however, chances are these tough plants will withstand dividing and replanting any time during the growing season.
Clear the area around the daylily plant. Remove annuals, tie back taller perennials and rake mulch to the side.
Prune the foliage and flowers to a few inches above the ground, making it easier to gain access to the root system of the daylily clump.
With a sharp garden spade or fork, begin cutting into the soil about one foot away from the plant. Daylilies' root systems spread wider than their above-ground parts.
Make a circle around the entire root ball, cutting into the soil as you go.
Lift the entire plant out of the hole.
Examine the root ball to find any obvious places to cut into the clump. Ideally, the center of the root system will yield an easily-accessible spot to divide the clump.
Place two garden forks back to back, with the tines intertwined, and press each fork outward. If you don't own garden forks, try one or two sharp spades or even a long, sharp kitchen knife.
Divide the two halves again, if desired, using the same method.
Dig holes for the new plants, either in the area in which the original clump was growing, or elsewhere in your yard. Make each hole slightly less deep than the height of the root ball, but six to nine inches wider.
Fill in each planting hole with soil, press down firmly and water well.
Apply a one-inch layer of mulch around the base of each daylily plant.