A good time to transplant peonies is in the fall when they have begun to go dormant. It is not advisable to transplant them in the spring.
Dig peonies out carefully to avoid root damage. If the plant is very large or old, it should be divided using a clean knife. Plant peonies with at least three feet of space around them, and be careful not to bury them too deeply. Water the transplanted peonies regularly until the ground freezes. Peonies are highly sensitive and may not bloom for several seasons after being transplanted. If peonies must be transplanted in spring or summer, take extra care in handling them. Get them transplanted quickly, and do not plant them any deeper than they were before.