When to Plant Peonies: Fall Timing by Region, Depth and Spacing

Peonies are long-lived perennials, and most flowering failures trace back to how and where they were planted. Ask Extension and Clemson both name planting too deeply as the most common reason a peony won't bloom, so depth matters more than the exact week. Wisconsin Extension describes three kinds sold in garden centers: herbaceous peonies that die to the ground each winter, woody tree peonies, and Itoh (intersectional) hybrids between the two. This guide is mainly about herbaceous peonies, the usual bare-root roots sold in fall.

When to plant peonies by region

Fall planting gives the roots several weeks to grow before winter, and the plant comes up as soon as spring arrives (K-State). If you buy bare-root peonies in spring, plant them as soon as the soil can be worked and expect the first year to be mostly leaves (GardenPal note). Use our planting calendar to see your first fall frost and count back.

How deep and far apart to plant peonies

Firm the soil around the roots and water well so the eyes don't sink (K-State). Good air movement helps limit disease (Iowa State), so don't crowd peonies against walls or shrubs. Because a peony can stay in one place for decades, choose the spot carefully the first time (GardenPal note).

Dividing and moving peonies

• When: September or October, the same window as planting (Wisconsin, Clemson, K-State).
• How: lift the clump, wash off the soil and cut it into pieces with 3 to 5 eyes each (Wisconsin, Minnesota). Minnesota Extension divides plants that are 3 to 5 years old and trims the roots to 6 to 7 inches.
• Replant shallow: eyes no more than 2 inches deep (Minnesota), or about 1 inch in the South (Clemson).
• Be patient: divisions take about three years to return to full bloom (K-State).

Why peonies don't bloom

The most common reason is planting too deep (Ask Extension, Clemson). Other causes that Clemson lists include too much shade, plants that are too young or recently divided, too much nitrogen, crowding by trees and shrubs, and not enough winter chilling in zones 8 and 9. Wisconsin also warns against too much nitrogen. If a mature peony stops flowering, check the depth first and lift and reset it in fall if the eyes are buried (Ask Extension).

Watering, feeding and fall cleanup

• Water: deeply every 10 to 14 days in dry weather rather than little and often (Clemson).
• Feed lightly: Clemson uses a low-nitrogen fertilizer such as 5-10-5 at 2 to 3 pounds per 100 square feet in spring when shoots are 2 to 3 inches tall. Too much nitrogen means leaves instead of flowers (Wisconsin).
• Fall cleanup: cut herbaceous peony stems to the ground after frost and throw the foliage out rather than composting it, to reduce disease (Clemson).
• Tree peonies are different: never cut them back to the ground; plant grafted tree peonies with the graft union about 1 inch below the soil (Clemson).
• Ants: ants on the buds are harmless and don't help the flowers open (Clemson, Wisconsin).

Cutting peonies for the vase

Clemson says to cut peonies at the soft-bud stage, when the bud feels like a marshmallow and shows color, and to leave at least three leaves on each stem so the plant can feed itself for next year. Botrytis blight and leaf blotch are the main diseases to watch for (Clemson); good spacing and removing old foliage in fall help (Clemson, Iowa State).

Peonies around the vegetable garden

Peonies are permanent, so plant them along the edge of the garden or at the end of a bed where they won't be dug up each season (GardenPal suggestion). They make a good partner for alliums, whose leaves fade as the peony foliage fills in; see when to plant alliums. Other fall jobs for the same weeks include planting tulips, planting garlic and dividing rhubarb. Lilies bloom just after peonies and are also planted in fall; see when to plant lilies.

Frequently asked questions

When is the best time to plant peonies?

Early fall for bare-root peonies: September in Iowa (Iowa State), late September to October in Kansas (K-State), and at least six weeks before the ground freezes (Ask Extension). Potted peonies can be planted any time during the growing season (Iowa State).

How deep do you plant peonies?

Set the eyes 1 to 2 inches below the soil (Iowa State, Wisconsin), and no more than 1 inch deep in the South (Clemson).

Can I plant peonies in spring?

Potted peonies, yes (Iowa State). Bare-root peonies are best planted in fall, when they have time to root before winter (K-State, Clemson).

Why is my peony not blooming?

Usually because it is planted too deep (Ask Extension, Clemson). Too much shade, too much nitrogen, recent division and lack of winter chill in zones 8 and 9 are other causes (Clemson).

When should I divide peonies?

In September or October, into pieces with 3 to 5 eyes (Wisconsin, Minnesota). Expect about three years to full bloom afterward (K-State).

Do peonies need ants to open?

No. Ants are attracted to the buds but are harmless and don't help them open (Clemson, Wisconsin).