Peonies are long-lived perennials that produce robust, vibrant blooms in the spring and lush foliage for the remainder of the growing season. Originating in Asia over 1,600 years ago, the popular herbaceous peony and the slow-growing tree peony thrive in colder climates, which allow them to complete their full growth cycle and provide bountiful blooms year after year.
Peonies do not need to be trimmed, or pruned, until after the foliage has died off in the fall. After the first heavy frost, cut all stems off, leaving only 3-inch stalks. This helps prevent fungal diseases from developing over the winter months. Tree peonies do not need to be cut back at all.
Peony blooms should be removed as soon as they die off, just below the base of the flower, without removing remaining foliage on the branch. If you leave the flowers intact, they produce seed which then drains the food reserves of the entire plant. If you like to use peonies for cut flower arrangements, do not take more than 1/3 to 1/2 of the blooms from each plant. Removing too many blooms can impact the peony’s blooming power in the next season.
The optional practice of disbudding peonies will produce larger blooms, reduce weight on stems that causes them to fall during heavy rain and winds, and also strengthens the root system of first-year plants. When all but the top bud on the branch have grown to at least pea size, pop each one off directly at the base of the stem, leaving behind any small leaves. If you do choose to disbud your peonies, you may want to stake the remaining blooms for added support.