Dividing the plants and giving them more growing room will revitalize daylilies. The ideal time to divide daylilies is in late summer to early fall, after they are done blooming for the season.
To divide daylilies, use a sharp spade or garden fork to lift the clump from the soil, carefully digging about 6-12 inches from the plants to completely pry out the clump. Next, take two garden forks - garden forks look like smaller, stronger versions of pitchforks - and push the forks back to back into the midst of the clump. Then gently pull the garden fork handles apart, forcing the roots to separate into two smaller clumps. If the clump is really large, you may have to separate it into several divisions.
To replant the daylily divisions, start by digging a wide, shallow hole about six inches wider than the root ball of your daylilies. Place the root ball in the hole at the same depth the plant was at before it was dug up. Tamp the soil into place, water thoroughly and add an inch of mulch around the plants to keep down weeds and help the soil retain moisture. Trim back the foliage to about 12 inches to help the plant put its energy into reestablishing itself in its new home. The next summer, your daylilies will reward your efforts with bountiful blooms.
