How to Divide Perennials

Perennial plant division is a straightforward gardening technique used to keep your garden healthy by splitting overgrown clumps into smaller, vigorous plants. You'll know it's time for dividing perennials when clumps become dense, the interior becomes disappointingly unproductive, and the flower show isn’t as prolific as it was in previous years.

When should you divide perennials?

Early spring is the usual time for dividing most perennials, though some plants (notably poppies and peonies) thrive when divided in the fall. Good timing is important to give the divided plants the best chance of prospering.

How do you dig up the clump?

Dig up the clump carefully, taking care to get as much of the root system as possible without damage. Most roots sit in the top 12 inches of soil, and the root mass will usually be the diameter of the plant plus 3 to 6 inches beyond it. For digging and transplanting, going larger than this shouldn't be necessary.

How do you break the plant into divisions?

Use a sharp spade to cut or cleanly break the clump into two or more pieces (divisions), ensuring each piece has an obvious growing point and some roots.

Work quickly so the plant parts don't dry out too much. You can cover them with a tarp or mist them occasionally if need be. Discard any unproductive, shriveled, or rotten parts. While you can pry apart fibrous-rooted perennials with your bare hands, all others require sharp, strong, clean tools equal to the job, like a stout knife, a trowel, or two gardening forks braced back-to-back. Leave soil surrounding the roots to protect root hairs from drying out and becoming damaged.

How should you replant the new pieces?

Replant your new divisions in good (fertile and well-drained) ground immediately to start propagating perennials successfully.

Prepare your new beds in advance so you can move quickly. You can plant some in the same spot—perhaps after adding a dose of organic matter—and place the others elsewhere in your yard. Water the divisions well and look in on them regularly. They should quickly generate new, smaller, vigorous plants!

Frequently asked questions

Q: Why is the interior of my perennial clump dying out?
A: When perennials grow in ever-denser clumps, the center often becomes unproductive due to overcrowding. Dividing perennials revitalizes the plant and encourages new growth.

Q: Can I share my new plant divisions?
A: Yes! Propagating perennials is a great way to multiply your garden's yield. The extra divisions are perfect for sharing with other gardeners.