Peonies are a beloved garden flower, but many gardeners are unsure about how to prune them. Whether you have herbaceous peonies, shrub-like tree peonies, or intersectional hybrids, the pruning methods vary slightly based on the type. This guide will explain the correct way to prune each type to keep your peonies healthy and blooming beautifully.
Pruning Herbaceous Peonies
Herbaceous peonies, which are the most common, are straightforward to prune. These plants die back to the ground in winter, and new growth emerges in spring from buds located on thickened, tuberous roots.
The best time to prune herbaceous peonies is in late winter or early spring before new growth starts. You can cut them back to the soil line. Some gardeners prefer to prune them in the fall after the stems have dried up, but this isn’t necessary. In fact, leaving the dead growth over winter provides natural protection to the new growth buds. However, if your peony has developed unsightly leaf spots during the fall, an early prune might help prevent the spread of fungal spores like Septoria paeonia, which causes brown, round spots with red-brown edges.
Pruning Intersectional Hybrids (Itoh Peonies)
Intersectional hybrids, or Itoh peonies, are a cross between herbaceous and tree peonies. These plants have partially woody stems at the base, but they still die back in winter. You should prune them much like herbaceous peonies by cutting back the stems almost to the ground. However, leave the short, woody stubs, as they may have buds that will sprout in the spring. Most of the new growth will come from the root buds, similar to herbaceous peonies, but some of the old woody stems may die back too, which is perfectly normal.
Pruning Tree Peonies
Tree peonies differ significantly from herbaceous varieties. These are woody shrubs with a more permanent structure. In general, tree peonies require little to no pruning. They naturally grow larger and more beautiful with age. However, there are two situations where pruning is recommended.
- Encouraging Branching: If your tree peony has just a few bare basal stems, a light prune in early spring can encourage more branching.
- After Damage: Tree peony stems are brittle and can break under heavy snow. If this happens, trim the damaged branches back to just above a healthy bud. If the plant is left with only a couple of main stems, consider a more significant prune in late winter to rejuvenate the shrub. Be prepared that a severe prune might result in no flowers the following year.
General Tips for Pruning Peonies
- Remove Dead Flowers: For all types of peonies, removing faded flowers helps prevent seed formation and encourages a tidier plant.
- Watch for Disease: Fungal diseases like leaf spot can affect peonies, especially during damp weather. Early pruning of infected leaves helps reduce the spread of spores.
- Keep the Plant Healthy: Peonies thrive when given good care. Proper pruning is part of ensuring their health, so prune at the right time and avoid excessive cutting, which can stress the plant.