A peony can be any member of the Paeonia genus. Most peonies have herbaceous stems, but tree peonies (Paeonia suffruticosa) have woody stems, making them easier to transplant. You may need to transplant a mature tree peony when it becomes shaded by a tree or shrub.
Select a planting site. Tree peonies prefer full sun--at least six hours of sunlight each day--and well-drained soil. You can improve the drainage if necessary by working in compost, leaf mold or peat moss.
Dig a hole that will be able to accommodate the entire root system of the tree peony. Space the holes 3 to 4 feet apart if you're transplanting multiple tree peonies.
Cut the stems close to ground level in September. Dig well away from the plant to get as much the tree peony's extensive root system as possible. Plant the tree peony in the new location promptly.
Place the tree peony in the new location so the buds are no more than 2 inches under the soil. Fill the hole with soil and firmly pack it around the plant. Water the plant thoroughly.
Spread 4 to 6 inches of mulch, such as straw or pine needles, around the tree peony in late fall. Remove the mulch in the early spring before the tree peony begins to grow. Remove any flower buds for the first two years to encourage the transplanted peony to develop its roots and leaves.