September 4, 2002
Woodbury Bulletin
Betsy Halden

Divide peonies in September

Peonies are one of our favorite perennials. Many gardeners enjoy their big, full, colorful blooms in late May and June. As a young child I remember walking with my grandfather among his beautiful peonies. Many were over my head. Many of us grow up appreciating the plants and flowers for which our family members shared their love. Several years ago I was part of a local historical society’s celebration of spring, and we used peonies to decorate the May pole. Their fragrance heightened the enjoyment for all those taking part in the festivities.

The peony has been a popular perennial in American gardens since the 1800’s. The peony is hardy, dependable, long-lived, and easy to grow. Gardeners value the peony for its large, colorful flowers in spring and its attractive, season-long foliage.

Peonies can be left und

isturbed in the garden for many years. Occasionally, however, it becomes necessary to move established plants. Peonies shaded by large trees or shrubs bloom poorly and should be moved to a sunny site. The redesign of a perennial bed or border may require moving the peonies. Large, old plants may become overcrowded and flower poorly. To improve their performance, large, poorly blooming peonies should be dug, divided, and transplanted.

Moving established plants is a simple procedure. Cut the peony stems near ground level in Septem

ber. Then carefully dig around and under each plant. Try to retain as much of the root system as possible. Promptly replant the peony in a sunny, well-drained site. Do not allow the root system to dry out.

Division of large peony clumps requires a few additional steps. After digging up the plant, gently shake the clump to remove loose soil from the root system. Using a sharp knife, div

ide the clump into sections. Each section should have at least 3 to 5 buds (eyes) and a good portion of the root system.

Peonies perform best in full sun and well-drained soils. When selecting a planting site, choose an area that receives full sun. Avoid shady areas near large trees and shrubs. You can often improve poorly drained soils by working in large amounts of compost or peat.

When planting peonies, dig a hole large enough for the entire root system. Place the peony plant in the hole so the buds are 1 to 2 inches below the soil surface. (Peonies often fail to bloom satisfactorily if the buds are more than 2 inches deep.) Fill the hole with soil, firming the soil around the plant as you backfill. Water thoroughly.

In late fall, November, apply a 2 to 4 inch layer of mulch over the newly planted peonies. Straw is an excellent mulch. Mulching will prevent repeated freezing and thawing of the soil during the winter months. it is the freezing and thawing and the resulting heaves in the soil of the roots that damages the plants. Remove the mulch in early spring before growth begins.

Transplanted peonies will not bloom well the first spring. It’s advisable to remove flower buds that form the first year in order to maximize plant growth. Transplanted peonies should bloom well by the third or fourth year.

The University of Minnesota Extension Service has several publications with topics of current interest. “Dividing Perennials” is the title of an informative Yard & Garden Brief. A chart is included that lists which perennials should be divided in spring, late s

ummer, early fall or not at all. The August 15 Yard & Garden News has an article on West Nile Virus and another on why homeowners should be skeptical about using lime on their lawns. You can access these materials at www.extension.umn.edu.

If you are interested in becoming a University of Minnesota Extension Service Master Gardener, please contact the Washington County Extension Service office at 651.430.6803 or FAX your request to 651.430.6801. The deadline for applications is September 15.

Betsy Halden is a resident of Woodbury. University of Minnesota Extension Service and Iowa State University Extension Service materials were consulted in the preparation of this column. You can reach Betsy Halden at eahalden@comcast.net