Answer: It is possible that they are old and need to be divided, but peonies are very long lived. More frequent causes for peonies to decline would be lack of sunlight due to the growth of neighboring trees over the years, and poor fertility due to either competing with nearby plants or a need for fertilization. You might try giving them a top dressing of compost, well rotted manure, and/or a complete fertilizer in very early spring and again in late spring and see if that helps things along next year. Another possibility is that repeated overmulching has caused the crowns to become too deeply planted. A layer of two to three inches of mulch is sufficient.
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