Fall Is the Best Time to Divide Peonies to Boost Blooms—Here’s How

Unlike many perennials that die out after a few years, garden peonies boldly flower for decades with little or no care, provided they receive ample sunlight and regular water. In most cases, division is not required for these perennials to flower and thrive. But if your peonies are flowering less over time or nearby plants are encroaching on their growing space, dividing them in fall is one simple solution.

Use these step-by-step instructions to divide garden peonies correctly so each part will grow into a strong new plant to add to your landscape or to share with other gardeners. 

1. Time It Right

Garden peonies thrive when divided in early fall. Timing is critical. If you wait until mid- to late fall to divide a peony, you risk freezing temperatures, which prevent the plant from becoming established in the soil. Aim for early fall in most regions; late summer is best in northern locations (Zone 3).

Use the date of your first expected fall frost as a guide. Divide and replant peonies 4 weeks before the first anticipated killing frost in your area. The soil will remain warm enough for good root growth for several weeks after the first fall frost, giving peonies ample time to build a new root system.

2. Cut Back Foliage

Using sharp hand pruners, cut the plant back to ground level. This major trim will make it easier to dig and divide the plant. Cutting peonies back at the end of the growing season will not harm future growth, as all the necessary nutrients for regrowth are stored in the root system.

3. Dig Up the Clump

Use a sharp spade to carefully dig around the perimeter of the plant, using the stubble of stems as your guide. Then, sink the spade into the soil at an angle to gently lift the peony out of the ground. Work around the perimeter of the plant, lifting as you go. Peony roots extend about 6 to 8 inches into the ground.

4. Divide the Plant

After digging up the peony, gently shake the clump to remove loose soil so you can more easily see the root system. Look for pink growing points near the top of the root clump. These pink growing points are called buds or eyes. Each division needs 3 to 5 buds to support new growth.

Using a sharp spade or garden knife, slice the large clump into sections with 3 to 5 buds and ample roots per section. Large, long-established peonies are often divided into three or four sections. Always be mindful of the buds; be sure each division has at least 3 buds.

5. Select a Planting Location

Careful site selection is essential for long-lived peonies. Choose a planting spot where the division can remain undisturbed for decades. Each division needs a planting spot that is about 4 feet long and wide. Full sun is a must, along with well-drained soil. Beware of nearby trees and shrubs. Ask yourself whether they will cast shade on the peony in a few years.

6. Replant

Correct planting depth is essential when planting peony divisions. The pink buds should be covered by just 1 to 2 inches of soil. If divisions are planted too deeply, the buried buds will struggle to produce new growth, resulting in no flower production. On the other hand, if the peony buds are too close to the soil surface, they are prone to winter injury.

Dig a planting hole 1 to 2 inches deeper than the depth of the root mass and just as wide. Settle the division in the planting hole. Check the depth by placing the handle of a spade over the planting hole. The spade handle represents the finished grade; the buds should be 1 to 2 inches below the handle. Adjust the planting hole as needed and then backfill the hole, lightly tamping the soil as you go to eliminate air pockets around your newly planted peony division.

7. Water

Water the newly planted division well right after planting and then weekly when it doesn’t rain. Continue watering until the ground freezes. Consistent water will help the division establish a strong root system that increases the chances of multiple flowers in spring.

8. Apply Mulch

In late fall, spread a 6-inch layer of mulch over the division to protect it from freeze-thaw cycles. Repeated freeze-thaw cycles can heave the newly rooted division out of the ground, exposing the tender roots to extreme temperatures. Rake away the mulch in spring.