Although peonies may be divided right after they bloom in early summer, many gardeners prefer to take on this task in the fall. The Flower Gardener’s Bible, by Lewis Hill and Nancy Hill, explains how to divide them in four easy steps.
- Cut straight all around the peony plant with a spade or garden fork before tipping the plant out of the ground. If the plant is old, the roots may be as much as 3 or 4 feet long, but don’t worry if you break some of them.
- Use a strong spray of water to wash some of the soil off the root system so that you can see what you’re doing. If you can’t divide and replant the peonies immediately, place them in a cool, shady spot and cover them with a damp cloth so they don’t dry out.
- Use pruning shears or a large, sharp knife to cut the divisions apart. Be sure there are three or more “eyes” (the pinkish-white sprouts) in each division.
- Dig a large hole, amend the soil, then heap it up in the middle so that, when the division is in place, the point where the sprouts emerge from the root is only an inch below the surface. Planting peonies too deep is the most common cause of failure. Cover root with soil; water well.