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 eyes and good roots.
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. Leaf blotch develops during warm, moist weather.