How to Divide Perennials

Perennials earn their keep by coming back year after year, but they also issue a quiet demand: divide me or watch me fail. After three to five years in the ground, most perennials crowd themselves into dense clumps that bloom less, flop over, or die out in the center. Division resets the clock, giving you multiple healthy plants from one tired clump. The work is straightforward but the timing matters. Spring division gives plants a full season to establish before winter. Fall division, done six weeks before first frost, works for spring bloomers that would otherwise lose their flowering energy to recovery. Either way, you are separating roots that have grown together, which means working quickly and keeping them moist. A plant out of the ground is on the clock.

1. Hydrate Before You Dig. Soak the soil around the perennial to a depth of eight inches. Moist soil holds together better when you dig, and hydrated roots handle the shock of division without wilting. If the ground is already wet from recent rain, skip this step.
2. Lift the Entire Root Ball. Push your spade straight down in a circle six inches beyond the plant's outer leaves. Rock the spade to loosen the root ball, then slide it under and lever the whole mass out of the ground. Don't try to dig out just part of the plant — you need the whole thing.
3. Expose the Crown Structure. Remove enough soil to see where the roots connect and where natural divisions exist. For plants with dense root systems like daylilies, use a hose to wash away soil. For looser systems like hostas, shaking is enough. You want to see the crown structure.
4. Separate Into Viable Pieces. Pull apart loose clumps by hand, keeping three to five shoots per division. For woody or tangled crowns, push two garden forks back-to-back into the center and lever them apart. For extremely tough roots, use a sharp spade to cut straight down through the crown. Each division needs both roots and shoots.
5. Prune to Reduce Shock. Snip off any broken, mushy, or blackened roots with pruning shears. Cut the foliage back by half to reduce water loss while the roots reestablish. For plants divided in fall, cut foliage to four inches above the crown.
6. Get Them Back in Ground Fast. Dig holes as deep as the original root ball and twice as wide. Set each division so the crown sits at ground level, spread the roots out, and backfill with the excavated soil. Firm the soil with your hands to eliminate air pockets. Water thoroughly until the soil is saturated.
7. Establish With Steady Moisture. Apply two inches of shredded bark or compost around each division, keeping mulch an inch away from the crown. Water every other day if it does not rain, keeping the soil moist but not soggy. The goal is constant moisture while new feeder roots develop.