Peonies (Paeonia sp.), unlike Hosta’s and other perennials, don’t need to be divided frequently. Some experts say peonies only need to be divided once every 10 years and others suggest once in 50 years is sufficient (UMN Extension Dividing Perennials, K-State Research and Extension, Illinois Extension College of Agricultural, Consumer & Environmental Sciences)! Iowa State University’s Extension Yard and Garden states peonies can live up to 100 years if well maintained (Iowa State Extension Yard and Garden). Many people divide them to create additional bushes or to share with others. Dividing peonies is not difficult but there are a few important points to know to be successful.  

The best time to divide or move peonies is late August through September but it is possible to do it at any time between spring (after the ground thaws) and fall (before the ground freezes). Moving them later than September in the fall is not advised because you need to give the peonies time to get their roots established before the ground freezes. 

The American Peony Society provides detailed information for digging, dividing, and replanting peonies (Dividing and Replanting Peonies). You can either dig the whole plant out or cut out a pie-shaped wedge. If you dig the whole plant out, you should plan to divide it as just moving the whole plant may result in decreased flowering for a couple of years. Peonies grow large, thick storage roots, making it difficult to get the whole extensive system that develops after three or more years of growth. This is important to know because when you dig the plant, you will want to ensure you keep a six-to-ten-inch length of these storage roots for replanting. 

To dig the whole plant, dig around 8-10 inches out from the plant and go around the whole plant. The first time you dig, you will want to dig straight down in a circle around the plant and the second round of digging should be angled inward. This allows you to undercut the roots. It is not recommended that you pry the roots out; instead, you should continue to go around the plant until you have loosened the whole plant and can lift it. If you try prying the plant out with your shovel or spade, you run the risk of losing good roots because they often break at the tops. Once the plant is dug out, shake off the soil and rinse the roots off. This will help you identify the ‘eyes’ or buds. 

When you divide the plant or if you elect to take a pie wedge approach, take a 6-8 section and cut straight down, making sure you get a minimum of 1-3 large buds. However, the University of Iowa’s Extension garden program recommends 3-5 large buds (https://www.extension.iastate.edu/news/yard-and-garden-how-divide-peonies). If you have fewer than two buds, it can take several years before the peonies will flower again. To cut through the roots, which are tough, use a very sharp knife. If you have only cut a wedge out of a peony plant, fill in the space you cut out with good soil. The remaining plant will close the gap. 

When you replant the peony / plant, you will want to select a site that receives at least six hours of direct sun and has well-drained soil. Dig about a one-inch-deep hole. Peonies prefer to have their eyes near the surface. If you plant them too deep, the plant will continue to grow but there will be no peony flowers. 

Whether your goal is to increase the number of peony plants in your own yard or share them with others, following these division steps will help you to end up with more beautiful peonies.

Photo Credits:

Michelle Scullard 1,3,4

University of Iowa Extension 2