When should I move my peonies?

We have several well-established, healthy peonies in the way of an addition to our house and need to move them soon to be ready when the contractors are ready to work on the house. Can they be moved now and how do you recommend doing so?

— Janelle Olivera, Shorewood

The best time to move your peonies is in early fall from late August to mid-September. This will give the plants time to settle in before winter. It is possible to move it in other seasons if necessary. I have had success moving peonies in spring and summer and even late October because of pending construction. You should be able to successfully transplant your peonies this fall. The key is to dig a large root ball and replant immediately, especially when transplanting at less desirable times of year.

To transplant, use a sharp, flat spade to make a cut around the peony in preparation for lifting the root ball. Angle the cut under the roots of the peony, starting a few inches away from the foliage at the base of the plant. Two to four inches away from the foliage should suffice — a healthy, vigorous clump may benefit from a slightly larger root ball and a less-developed plant could do with a smaller root ball. After cutting around the plant, use the spade to gently pry the root ball up. If the soil crumbles away from the edges, you may have made the root ball too big. A healthy plant with a good root system should pop right out of the ground. If you have sandy soil in your garden, the root ball may not hold up well. Water the new transplant in well and mulch. Provide supplemental water to the transplants throughout the remainder of fall and into November if conditions are warm and dry.

For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.