How to Divide and Transplant Peonies
Peonies are among the biggest and best blooms in the late spring garden. Their exuberant flower heads, heavenly scent, and ability to thrive for decades make them the perfect plant for mixed herbaceous borders, cuttings gardens, and floral hedges.
Although these easy-care perennials rarely need attention, there are times when it’s beneficial or necessary to divide and transplant peonies. Over time, the original planting site may have become too shady or there’s no longer good air circulation around the plants. You may be getting fewer flowers because too much soil has accumulated over the top of the roots. You might be moving and want to take your peonies with you or need to relocate the plants due to a renovation project. Or maybe you want to expand your flower garden and share some plants with friends. All are good reasons to dig, divide and transplant peonies.
When and How to Divide a Peony
These instructions are for dividing herbaceous peonies — the types that die to the ground each fall. With a little extra care, you can use the same approach to divide peonies that are intersectional hybrids (informally known as Itoh’s). Tree peonies may also be moved and divided, but the instructions are a bit different.
The best time to divide peonies is in the fall, once the red “eyes” (next year’s buds) are visible at the base of the plant. Start by cutting off all the foliage at ground level. Depending on the size of the plant, begin digging about 12” away from the center. Go slowly. Peony roots are brittle, and you want to maintain as much of the root system as possible.
Once the root ball is out of the ground, spray it down with water to remove most of the soil, especially from around the top of the plant. This will make it much easier to see the eyes. Look for a place where it may be possible to pull the clump apart. If not, use a sharp knife or pruners to divide it into sections. Each division should have at least 3 to 5 eyes and a healthy mass of roots. Divisions with less than 3 eyes will grow, but it may be several years before the plant produces flowers.
Replanting a Newly-Divided or Relocated Peony
Plant the peony divisions 3-4 feet apart in full sun and fertile, well-draining soil. Do not plant them near trees or shrubs, or in an already crowded flower bed where they would need to compete for water, nutrients, and light. Try to ensure there will be good air circulation on all sides of the plant. This will decrease the likelihood of disease in future years.
Dig a generous planting hole and mix in a shovelful of compost and a little all-purpose fertilizer. Position the peony division in the hole so the eyes are no more than 1-2 inches below the soil surface. If peonies are planted too deeply, they produce only foliage and no flowers. Backfill the hole with soil and water thoroughly.
In late November or early December, you can apply a 2” layer of mulch over the planting area to insulate the roots. Be sure to remove the mulch in early spring as soon as new growth emerges.