How to Split Peonies
Unlike most perennials, peony bushes do not need to be split periodically to thrive and flourish. In fact, they are happiest when planted once and then left alone. Well-established plants can produce beautiful flowers for more than 100 years. Unfortunately, peony plants can grow so large that they become unruly and cumbersome. With a little care, it’s possible to divide that voluminous peony bush into smaller, more manageable plants.
Things You’ll Need
- Plastic tarp
- Large rag or old towel
- Sharp knife
- Compost or fertilizer
- Decide which bush or bushes you will split. According to Martin Page, author of "The Gardener’s Peony," the optimum time is when the plant is between three and five years old.
- Decide when you will divide your bush. Preferred month is late August or September, on a sunny day where the temperature is moderate.
- Water the soil so it is easier to work a day or two before splitting your plant.
Dig up the plant
- Cut off dry and dead plant leaves. Cut down the stems to about two inches above the ground. Ensure that you do not cut off any of the "eyes" (small pinkish buds) that may be developing at the base of each stem.
- Use a pitchfork tine to draw a large circle in the dirt around your plant. Working within this area, use the pitchfork to gently loosen the soil.
- Dig carefully around your plant with a spade, following the circle you drew into the dirt,. While digging, ensure that you do not accidentally step on or damage the central portion of the plant because it controls plant growth.
- Use a shovel to gently lift the bush, preserving as many roots as possible. Work slowly. Peony roots are brittle when removed from the soil and will break easily.
- Put the roots on a plastic tarp and cover them with a rag until they become more pliable, which could take a few hours or a couple of days, depending on the size of the roots. Leave the dirt around the roots to prevent them from drying out.
Split the plant into sections
- Gently rinse off the dirt from the roots with a garden hose. This makes it easier to see the eyes at the stem’s base. Sturdy the root system to determine how you will divide it. Look for areas that are young and not diseased or rotting. If your plant is old, the best sections will be on the outer edges of the root system.
- Cut crown and roots into sections, using a sharp knife sterilized with alcohol. Each section should have at least one eye. Three to five eyes are preferable. Plants with three to five eyes will re-establish themselves more quickly and may bloom within two years.
- Remove and discard any rotting or damaged crown sections.
- Allow sections to air dry for about two hours or until a protective coating has formed over the newly cut roots. This prevents bacteria from developing on the roots.
Plant your new bush
- Dig a hole slightly wider and deeper than the root ball. Add bone meal to the hole and water until soil is moist.
- Place new section in the hole, ensuring the plant’s crown is no deeper than two inches below the surface.
- Fill hole with dirt. Tamp it gently with your foot to ensure there are no air pockets.
- Water plant thoroughly.
- Cover area around plant with mulch to protect it from harsh winter weather.