Growing Peonies

Peonies are perennial favorites in the flower garden. Few herbaceous plants can rival them for floral display and foliage. Their exquisite, large blossoms, often fragrant, make excellent cut flowers and the foliage provides a background for annuals or other perennials.

Flowering usually lasts one week in late spring to early summer. By selecting and planting early, mid- and late-season bloomers, flowering may be extended for six weeks. Flower color may be any except blue.

Peonies grow from two to four feet in height. Support is often required for tall, double hybrids. Peonies thrive in sunny locations and well-drained soils, tolerating a wide range of soil types. Best growth is in soil with a pH range of 6.5 to 7.5, deep and rich in organic matter. Organic soil amendments of all types are available at Little York Plantation. Consult our ‘Organic and Inorganic Soil Amendments’ Fact Sheet for types available.

Planting, transplanting and dividing peonies is best done in early fall but may be done in spring as soon as soils are workable. Each plant requires an area about three feet in diameter. Dig a generous hole, large enough to accommodate the roots, and incorporate aged organic matter in the bottom. Place the peony in the prepared hole so that the eyes (small, red-colored buds) are one to two inches below the soil’s surface. Backfill and water well.

Peonies may be left undisturbed for many years. A decline in flower production usually indicates overcrowding and the need for division. Carefully lift the clump and wash away the soil to expose the eyes. Using a clean, sharp tool, divide the clump into sections, each with three to five yes and good roots. Replant immediately, being sure to keep eyes exposed! Peonies planted too deeply will not flower.

Peonies have few pests or problems. The most frequently occurring pests are botrytis blight and leaf blotch, both fungal diseases. Especially prevalent during wet springs, botrytis affects leaves, stems and flowers. Spots appear on leaves, stems soften and decay, and flowers either rot or buds blacken and fail to open. Prompt removal of infected material and a thorough fall cleanup are essential for control. In spring when shoots emerge, use a fungicide labeled for botrytis according to package instructions. Leaf blotch develops during warm, moist weather. Glossy, dark purple spots form on the upper surfaces of leaves. Again, removal of infected leaves and good fall cleanup are necessary for control. Do not compost any yard waste that may be infected with any kind of disease, fungus or insect. This will simply result in making such problems spread year after year. Toss affected plant material into the trash and remove it from the property.

The only insect pests of any consequences on peonies are scales. Scales are seen on stalks and leaf bases in late summer and over-winter on the below ground portion of stalks. For control, remove plant material in fall and then apply a properly labeled insecticide in late May and mid-June the following year. The presence of ants on peony blossoms is neither beneficial nor harmful to the plant. Ants are simply attracted to the sugary liquid secreted by flower buds.

A common problem of peonies is the failure to bloom.It may be the result of:

planting too deeply
immature plants
excess nitrogen
inadequate sunlight
over crowding
insect or disease problems
late freezes
phosphorus and/or potassium deficiency
competition from roots of nearby plants

Credit: Ohio State University