Early fall is the best time to divide and transplant peony bushes. According to the North Dakota extension service, peonies should be divided every five years of growth to give the new bulbs room to grow. Locations for the transplants should be in well-drained soil with plenty of sunshine. In most all cases, large peony bulbs that are transplanted in early fall will grow well and bloom the following spring of the year.
Remove all dead stems and dying growth from the peony bush in early fall with the pruning shears.
Dig the bulbs from the ground. Allow for plenty of room when digging the plant from the soil. Keep in mind the existing soil line in relation to the crown of the bulbs. You will want to place the crown of the bulbs back into the ground at the same depth, about 1 inch below the soil line. The long pink bulbs may be slightly delicate so handle with care. If some of the smaller bulbs break free, plant them separately. During the second spring season, smaller bulbs will begin to show some blooms.
Dig the transplant hole or flowerbed with the shovel. If the growing bed is large, use a mechanical rototiller to work the soil. Remove all rocks and roots from the area with the hand cultivator. For maximum rooting, dig the flowerbed to a depth of at least 8 inches deep.
Plant the peony bulbs at the same depth as the plants were removed in Step 2, approximately 1 inch below the soil. Tamp the loose soil around the bulbs with your hands, gently. (Twenty-four-inch-diameter plants should be transplanted 12 inches apart. Space the bulbs further apart to create spaces between the individual plants.)
Water the bulbs into the soil to remove any air from around the bulb, and to improve soil to root contact.
Mulch around the plant as it begins to emerge from the ground. The mulch will aid in retaining moisture and deterring errant weed growth.