When to Plant Peonies

The rule: early fall, about six weeks before frost

Bare-root peonies go in the ground in late summer to early fall. NC State’s Clay County Extension Master Gardeners put it at about six weeks before the first frost, and the planting chart above runs from that point up to about the average first frost. The dates for your zone above show what that means where you live.

Potted peonies are different. Because their roots are already growing in soil, Iowa State says you can plant them any time during the growing season. The fall rule matters most for the bare roots that arrive by mail.

Why fall works best

In early fall the soil is still warm, so a newly planted root can grow new feeder roots before the ground freezes. Illinois Extension points out that fall soil holds its heat while air temperatures drop, which favors root growth over top growth. Nebraska Extension adds that early-fall planting gives the tubers time to settle in before winter.

A fall-planted peony comes up the next spring already anchored, and it is ready to put on leaves without having to build roots at the same time.

How the timing changes by region

Upper Midwest and North (zones 3 to 5). Plant in September. Iowa State names September for Iowa, and Wisconsin’s window is September to October. Do not wait until the ground is close to freezing. After it does freeze, Nebraska recommends about 2 inches of straw over new plantings to stop frost heaving, which can push young roots out of the soil.

Central states (zones 5 to 6). Nebraska Extension in Lancaster County calls October the best month to add new peonies or divide old ones. Prepare the bed two to four weeks ahead so the soil has time to settle.

Upper South (zones 7 to 8). NC State’s Clay County Master Gardeners plant about six weeks before the first frost, which in the North Carolina mountains is late August to early September. Clemson says fall is the best planting time for peonies in South Carolina and divides them in late September or October.

Lower South and warm-winter areas (zones 8b to 10). Timing is not the main problem here: winters are often too mild for herbaceous peonies to set flower buds. Clemson notes they often struggle in the lower South for lack of chill, and Texas A&M’s Bexar County office says San Antonio is too warm in winter and too hot in summer. If you try them, fall is still the planting season, and early-blooming cultivars give the best odds.

What happens if you plant early or late

Planting early in a hot, dry late summer means extra watering. Keep the soil moist, never soggy, until fall rains take over.

Planting late is the bigger risk. A root that goes into cold soil just before freeze-up has little time to grow, and freeze-thaw cycles can heave it out of the ground over winter. If you must plant late, water it in and mulch it once the ground freezes, as Nebraska Extension advises for all new plantings.

Whatever the date, depth matters more for flowering than timing. Set the eyes 1 to 2 inches below the surface. Even a perfectly timed peony may not bloom if it is planted too deep. Expect a new plant to take two to three years to bloom well. See how to grow peonies for planting and care.