Peony planting time

Horticulture Hints

Early fall is the best time to plant garden peonies. The old adage, “If a plant blooms in the spring, plant it in the fall” holds true for herbaceous peony plants. This rule of thumb is due to that in the fall, spring blooming plants are storing food reserves for winter, rather than putting their energy into creating flowers. Thus, with the extra energy needed to produce new roots, peonies planted in the early fall are able to establish sooner with less stress. Peonies planted later in the season may not have time to form new roots before winter.

Cooler temperatures of fall are also beneficial for peony planting, as with less water evaporation from heat, keeps moisture in the plant to aid in overcoming transplanting shock. In late autumn, established peony plants go dormant and start to form new feeder roots, this natural occurrence is another reason early fall the best time for planting.

Peonies typically do not bloom the first year after planting and need three to four years to reach full bloom production. Other reasons for peonies that do not bloom include planting in a shady location, as they need full sun to do their best. Planting too deeply will also cause lack of flowers, so do not plant peony bud eyes more than two inches deep, or flowering will not occur. Plants that are 15 to 20 years old also may not bloom, if they have become too crowded or have competition from tree roots for food and water.

Fall is the time to cut and remove or mow peony foliage down to the ground. This helps to prevent fungal disease spores from overwintering and infecting new plant growth in the spring.

For additional information on planting peonies, the ISU publication “Growing Garden Peonies” is available at: https://store.extension.iastate.edu/Product/4709 to download.

Did you know? Peonies can live for 100 years or more. A common question I receive throughout the year is how to rescue grandma’s peonies from the family farm. Although now is the best time for transplanting peonies, if it becomes necessary, they can be divided any time of year, but will require additional care for survival.

Questions? Contact McCormick at yvonne@iastate.edu for information or advice.

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