Peonies, a sturdy, dark green-leaved bush, were found in China, Siberia and Japan 2,500 years ago and eventually spread to Europe. The plants arrived in North America from Europe in the 1800s and some of those older cultivars are still around in the 21st century. Vintage peonies tend to do better in southern parts of the country. More cold-resistant peonies are bred to flourish in northern states. Peony flowers are lush, heavily scented, come in a number of colors, principally pink and white, and have a variety of petal styles. They bloom for just two weeks, so plant early- and late-flowering peonies to enjoy them longer.
Peonies need cold weather to flower. Most contemporary cultivars were bred for northern gardens where cold weather comes with the turf. In milder climates, like those in some southern states, peonies are best planted in the early fall, in September or October. The plants establish healthy root systems over the winter and will likely begin blooming the first spring after planting.
In colder climates, areas like Minnesota that get cold weather early and experience severe winters, peonies may be planted in late summer or early spring. In the cool weather of a northern spring, the plants will get the jolt of cold that stimulates flowering. If they go into the ground in mid to late August or early September, they will have time to acclimate to their setting before a hard winter freeze.
Peonies don’t like to be disturbed or moved so a transplant can go for a season or so without blooming. Avoid moving peonies whenever you can because transplants may take two to three years to settle in and begin producing flowers normally. Spring transplants are most likely to skip at least one flowering season. To minimize trauma, be sure the new location is sunny, protected from wind and has good draining soil to give transplants a strong start. Prepare composted, permanent new locations well in advance. Since peonies aren’t often moved and grow very deep roots, the only time you can prepare their site for optimal growth is before they move in.
Divide peonies in the fall. In every growing zone, peonies prefer to root and chill so separate large plants into several plants in September and you may see flowers in spring. Dig up the plant and carefully split it in sections with a sharp knife or shovel edge. Or, use a sharp spade to cut through part of a large peony plant, leaving one section in its original site and replanting the rest. Smaller divisions will take longer to acclimate and begin to flower, sometimes two or three years longer.