Peonies (Paeonia spp.) produce their large flowers in early summer, but the green, shrublike foliage provides garden interest until fall, when proper care aids the chances of vigorous blooming the following year. These long-lived perennials, which grow in U.S. Department of Agriculture plant hardiness zones 3 through 9, benefit from annual fall pruning and cleanup, which prevents fungal problems like botrytis blight. Peonies rarely need dividing. They only benefit from division when the plants become overcrowded, which can take 10 years or longer, or when weeds and grass invade the peony clumps.
Cut back the peony foliage to within 2 inches of the ground with sharp shears. Cut it down only after the foliage begins to yellow and die back naturally in fall.
Remove any fallen leaves, weeds and plant debris from the bed before winter. Move any dirt or plant material lying on top the peony crown, which is where the stems emerge from the roots at the soil surface. Dead plant material can harbor fungal spores and insect pests during winter.
Spread 1 inch of compost over the soil, taking care not to cover the peony crowns. The compost breaks down into the soil over winter, adding organic matter and trace nutrients that help revitalize the garden bed.
Loosen the soil around the roots of the peony with a trowel and lift the roots from the ground if they require division. Slice each root clump into two or three sections with a sharp knife so that each section contains at least three buds on the top surface. Buds resemble raised white nodules. Plant each peony division into the bed so that the top buds sit 1 inch beneath the soil surface. Space the plants about 2 feet apart in all directions.
Cover the soil with 1 inch of bark or leaf mold mulch to provide soil insulation during winter. These organic mulches break down over winter, which provides even more natural nutrients to the peonies when they resume growth in early summer.
Things You Will Need
- Bark or leaf mold
- Peonies may not bloom fully the first one or two years after dividing, but they should fully recover by the third year.
- Rinse the cut surface of each peony division with a solution of one part bleach and nine parts water to minimize fungal and disease problems after replanting.
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