How to Divide Tree Peonies
Tree peonies produce blooms similar to the herbaceous peony varieties. Tree peonies have woody stems and may reach heights up to 5 feet tall. While they grow from roots the way herbaceous varieties do, tree peonies are very slow to grow. Tree peonies aren’t often divided, but it can be done if the plant becomes overgrown. Divide older tree peony plants in fall eight weeks before the first expected frost.
Things You’ll Need
- Pruning shears
- Prune the peony down to half its height, removing all the foliage from the plant. Use sharp shears that have been cleaned prior to use to prevent the spread of disease to the plants.
- Dig 12 inches out from the stems of the peony and down to a 12 inch depth. Slide the shovel under the root system and lift the peony from the ground.
- Rinse away the excess soil clinging to the roots with running water. Wash the roots until you can clearly see them and where they join together.
- Cut apart the roots with a sharp knife, leaving at least one root attached to each woody stem of the tree peony plants. Dispose of any stems or roots that shriveled or have soft rot spots.
- Prepare a well-draining garden bed in partial sunlight. Loosen the soil to at least a 12-inch depth with a hoe.
- Dig 10-inch-deep planting holes for each peony division. Work a general purpose fertilizer into the bottom of each hole, following label instructions for application amounts.
- Plant the peony division in the hole so the top of the root system is 3 inches beneath the soil surface. Firm the soil around the plant and water thoroughly afterward.