When they become overgrown and stop blooming well, it's time to dig up clumping perennials and cut them apart. By dividing a plant into sections ― each with roots attached ― you end up with both a reinvigorated smaller clump to set back in the same spot and others to use elsewhere in your garden.
Most clumpers look better and produce more if you divide them every three or four years. Blooms will be larger and more abundant, and foliage will look lusher. Divide spring-blooming perennials in fall, and fall-blooming perennials in spring. If you live in an area with harsh winters, divide the plants, then get them back in the ground six to eight weeks before the first hard freeze.
While the process might look daunting for first-timers, dividing plants is very easy ― almost foolproof. Just follow these steps.
Division in 4 easy steps
A mature daylily is ready for refreshing when bloom is sparse and clumps are tightly packed. Dividing will revive the main clump and produce additional plants.
1. With a shovel or spading fork, loosen the soil a few inches around the base of the entire plant. Slide the shovel under the roots, then lift up the whole clump; keep as much of the rootball intact as possible. (If clumps are too large or heavy to move, divide them where they are.)
2. Shake or gently brush off the excess soil from the plant's rootball. Then divide the clump into two or more sections. Use sharp pruning shears to cut apart smaller clumps, and a shovel or spade to carefully poke through the base of larger or more fibrous-rooted clumps.
3. Pull divisions apart by hand ― each with a mass of roots and foliage attached. Continue dividing if you want even smaller clumps.
4. Snip off any damaged roots or foliage, then replant divisions as soon as possible in well-amended soil in the ground or in containers. Water well.
Divide these plants in fall
Gaillardia x grandiflora
Santa Barbara daisy