How to Divide Peonies in the Winter

Peonies are perennials that bloom year after year from the same root system. A clump of peonies features large, colorful blooms and may last for up to 100 years. This lifespan means that peony plants become extremely large and may overwhelm a given planting site. Gardeners avoid overcrowding by digging up peony roots during their dormant period and dividing them. Although the best time for this division is September, you can dig up and divide peonies through winter into the spring.

Difficulty:

Moderately Easy

Instructions

Things You’ll Need

• Quick-draining soil
• Organic compost
• Spade
• Knife
• Pruning shears
• Mulch

1. Divide and move peonies in the morning, when the air is cool and moist, to keep the roots of the plant from drying in midday heat.
2. Prepare a new site before you begin, for a quick and easy transfer. Choose a new site that gets full sun all day, and amend the soil to a depth of 12 inches with a mixture of half quick-draining soil and half organic compost. Plan to plant new peony plants 3 to 4 inches apart, to give them adequate space for growth.
3. Prune your established peony plant to within 2 to 3 inches of the ground, to help the plant conserve its resources during the process. Dig up the root system of the plant, but be careful not to damage any of the roots during this process. Pull the root system out of the ground.
4. Brush the dirt from the root system so you can see it clearly, and look for natural divisions, where the root system is growing new systems. Cut the peony root ball at these natural divisions, but make sure that each section has three to five buds of its own and a full set of roots.
5. Replace the original peony bush in its planting site, and move new peonies to the new planting sites. Plant them so that each bud has 1 to 2 inches of soil over it, and water each with 1 inch of water. Mulch the new peonies with 4 inches of straw or grass clippings, to keep them warm until spring.