Knowing when to prune peonies is important if you want to keep your plants in good health and ensure maximum flowering next year.
Learning how to grow peonies is one of the most rewarding pursuits in the garden. Few other plants offer such a wide variety of shapes and colors, from the purest white to lemon yellow, soft pink and the deepest red.
“Famous for their oversized flowers, peonies are a valuable landscape plant, often used for cut flowers,” says Lindsay Pangborn, gardening expert at Bloomscape (opens in new tab).
“Pruning peonies is an important task, but it’s important to think about the timing. It’s a careful balance between aesthetic and phytosanitary considerations.”
In addition to knowing when to prune peonies, knowing when to plant peonies is also important when adding new varieties to the garden. If your peonies aren’t blooming, this guide will help you.
When to Prune Peonies – Expert Advice
Your local climate may affect when peonies need to be pruned back, as peonies in warmer zones bloom earlier than those in cooler zones – check your USDA plant hardiness zone (opens in new tab). Peonies can be grown in zones 3-9, depending on the variety.
“Depending on where you live, the growing season for peonies can be anywhere from April to June,” says Gabriel J. Croteau, master gardener and consultant at Juliei Salone (opens in new tab).
“It may be tempting to prune peonies as soon as the leaves start to look bad, but ideally you’ll have to wait until fall to prune them.” That’s because the plants still depend on getting their energy for next year’s growth – and therefore earlier pruning could affect next year’s buds.”
When fall sets in and peony leaves turn yellow or brown, it’s time to prune.
“Bring them right back to about 2.5 cm,” says Jennifer Green, a botanist and expert on positive bloom (opens in new tab). “If the plant is badly damaged or overgrown, you should cut it as close to the base as possible.
“You can also remove healthy branches that are touching and remove the less developed branch with fewer buds.”
Can I prune my peonies in August?
August is not the best time to prune peonies as the foliage cannot absorb as much energy as it needs for the following year.
“Foliage on peonies tends to dwindle beginning in August, as the plant then begins to naturally divert energy away from the growing leaves and to underground bulbs instead. These bulbs allow the plant to store energy for the next season,” explains Pangborn.
“Although the leaves may not look good, it’s best to leave them in place so they can continue to photosynthesize and collect energy for the plant.”
Cut back peonies in spring
Unless you prune back old shoots from the previous year, do not prune your peonies in spring as this could damage the plant and prevent flowering.
However, there is an exception to the rule. “The only peony you should prune in the spring is a tree peony,” says Croteau. “You wouldn’t prune them back in the fall like a herbaceous or Itoh peony.
Early spring is the best time to prune tree peonies.
Do peonies need to be pruned back for the winter?
It is best to prune your peonies in the fall before winter and discard any dead plant matter.
“Peonies are prone to agaric problems, and if infected foliage is left on the plant through the winter, new growth can be exposed to harmful pathogens that have overwintered on the old leaves,” says Pangborn.
Pruning peonies before winter also keeps your garden tidy. “If you don’t cut them, the leaves and stems will spoil, become mushy and fall to the ground,” says Green.
Can you prune peonies after they bloom?
“You shouldn’t prune peonies after they’ve bloomed because the leaves do a lot of work during the growing season to gather energy for the plant. However, you should kill peonies after they bloom,” says Pangborn.
Always use clean, sharp pruning shears to remove faded flowers to avoid risk of disease transmission.
“Leaving the old buds on can contribute to fungal growth on the plant and make it unsightly,” adds Pangborn. “It’s also best to remove any stems that recede during the season to prevent the spread of disease.”
What Happens If You Don’t Prune Peonies?
If you don’t prune peonies, the old foliage will become unsightly over the winter and spring – but they should still bloom the following year.
“Keep in mind that this increases the likelihood of old fungal problems being carried over to the tender new growth in the spring,” Pangborn adds.