Fall Care of Peonies

FOR IMMEDIATE RELEASE
October 2, 2009

Peonies often grow and flower for many years, and they usually do not need frequent division like other perennials. Established clumps have remained undisturbed for 25 or more years and still flowered well. However, depending on site and growing conditions, crowding can occur. That's when plants should be lifted and divided.

Tony Bratsch, University of Illinois Extension horticulture educator, offers the following advice.

The time to dig, divide and re-plant peonies is late September through October. Soils should be well-worked and amended with sufficient phosphorous and potassium before planting. Peonies prefer a neutral to slightly acidic soil; they will not do well in soils that are extremely acid. After determining soil pH, use lime to increase pH in acidic soils. Then later, add lime to the bed surface, as needed, every two to three years to maintain proper pH. Contact the Extension office, 439-3178, if you need information on testing your soil pH.

Before digging, cut back the old tops. Lift plants with as much soil around the roots as possible. Using a sharp knife, carefully separate the clump of roots, leaving buds or "eyes" on each new planting piece. Reset with the buds no more than 1 inch below the soil surface. If buds are deeper than this, they may not flower normally. Roots beneath the growth buds should be set deeper and positioned as they were previously growing.

When peonies are finished flowering next year, cut off the flower head or seed pods. Allow as much foliage as possible to remain, and if desired, stems can be cut back to form a rounded bush.

Peonies make an attractive green plant for the summer with proper flower removal and shaping, and they can develop outstanding fall foliage color. Once the tops are frost-killed, trim stems to the ground. Apply a shallow leaf or bark mulch to minimize frost heaving of the bed area.

For more information about peony care and other perennials, visit our Gardening with Perennials website: http://urbanext.illinois.edu/perennials

Source: Anthony Bratsch, Extension Educator, Horticulture, bratsch@illinois.edu