If maintained properly, peonies can thrive for up to 100 years in a garden. September is the best time to transplant  and divide peonies, although they do not have to be divided on a regular basis, according to horticulturists with Iowa State University Extension and Outreach.

To divide, cut peony stems near ground level and carefully dig up the plants. Next, wash or gently shake off the soil and using a sharp knife, divide the clump into sections with each section having three to five buds and a good root system. The horticulturists note that divisions with fewer than three buds may take two or more years to flower.

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