Learning how to grow peonies is one of the most rewarding gardening pursuits. Few other plants offer such a vast range of forms and colors, from purest white, through lemon yellow, softest pink and deepest red. ‘Renowned for their oversized blooms, peonies are a prized landscape plant often used for cut flowers,’ says Lindsay Pangborn, gardening expert at Bloomscape (opens in new tab). ‘Cutting back peonies is a critical to-do item, but it’s important to think about timing. It’s a careful balance of aesthetic and plant health considerations.’ As well as knowing when to cut back peonies, it’s also important to know when to plant peonies if you’re adding new varieties to the garden. Plus, if your peonies are not blooming, this guide will help.
When to cut back peonies – expert guide
Your local climate can affect when to cut back peonies as those in warmer zones will flower 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 between 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 looking bad, but you ideally need to wait until fall to prune them. That’s because the plants are still relying on getting their energy for the following year’s growth – and so cutting them sooner could affect next year’s flowers.’ When fall sets in, and the peonies’ leaves change color to yellow or brown, then it’s time to make the cut. ‘Take them right back to about 1 inch (2.5cm),’ says Jennifer Green, botanist and expert at Positive Bloom (opens in new tab). ‘If the plant is severely damaged or overgrown, you should cut it as close to the base as possible. ‘You can also remove healthy branches that touch each other, taking away the less developed branch with fewer buds.’
Can I cut my peonies back in August?
August is not the best time to cut back peonies, as it doesn’t allow the foliage to absorb as much energy as it needs for the following year. ‘The foliage of peonies tends to decline, beginning in August, since this is when the plant naturally starts diverting energy away from growing leaves and instead to underground tubers. These tubers allow the plant to store energy for the next season,’ explains Pangborn. ‘Though the leaves may not look great, it’s best to allow them to remain so that they can continue to photosynthesize and gather energy for the plant.’
Cutting back peonies in spring
Unless you are trimming old growth left over from the previous year, you must not cut back your peonies in the spring, as this could harm the plant and prevent it from flowering. However, there is one exception to the rule. ‘The only peony you should trim in the spring is a tree peony,’ says Croteau. ‘You wouldn’t cut it back in the fall like you do a herbaceous or Itoh peony. Early spring is the best time to prune tree peonies.
Do peonies need to be cut back for winter?
It’s best to cut back your peonies before winter in the fall, and discard all dead plant matter. ‘Peonies are susceptible to foliar fungal issues, and allowing infected foliage to remain on the plant through winter can expose new growth to damaging 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 deteriorate, become mushy, and fall to the ground,’ says Green.
Can you cut down peonies after they bloom?
‘You should not cut back peonies after they bloom, since the leaves do a lot of work over the growing season gathering energy for the plant. However, you should deadhead peonies after they bloom,’ says Pangborn. Always use clean, sharp pruners to remove spent flower blooms, to avoid the risk of disease transference. ‘Allowing the old blooms to remain can contribute to fungal growth on the plant, along with being unsightly,’ adds Pangborn. ‘It’s also best to remove any stems that are declining throughout the season in an effort to keep disease from spreading.’
What happens if you don’t cut back peonies?
If you don’t cut back peonies, the old foliage will become unsightly over the winter and into the spring – but they should still flower the following year. ‘Bear in mind this increases the chance that any old fungal issues are transferred to the tender new growth in the spring,’ adds Pangborn.
