Winterizing peonies: how to keep these beautiful plants safe in cold weather

Their big, blousy blooms might make you think that winterizing peonies is difficult if they're going to survive harsh winter weather. But despite their delicate looking flowers peonies will actually survive the harshest winter weather as they are hardy to about -4˚F (-20˚C). In fact, the good news is that a cold winter means they will flower better and grow back stronger the following summer.

Looking after your beautiful plants properly during winter is a key part of growing peonies successfully. For that reason, it's best to plan ahead and begin preparing them for cold winter weather in fall. 

As with other perennials, this is done by cutting back the growth that was made during the current season. This will help to ensure that your plant has enough energy stored over winter and can quickly regrow next spring.

Where to start with winterizing peonies

To ensure your peonies survive winter and to give them the best chance of blooming in the spring, it's sensible to get them ready before the cold months set in and protect plants from frost. So be sure to add peony prep to your fall gardening checklist. 

Winterizing peonies successfully depends on a few key things. 'It means ensuring your peonies have a nutrient-rich soil, removing any dead or diseased foliage, providing extra insulation during the coldest months, and making sure they have the right amount of light and moisture,' says gardening expert Mike Futia of Nerd Lawn. 'With the right level of care and attention, your peonies will be able to survive even the coldest winter months.'

Cutting back peonies for winter

By fall it might look as though your peonies are dying, but in fact they’re in the process of developing flowering buds for the following summer. Even if your peonies look dead don't be tempted to start cutting back the foliage until late fall as they're still growing. The leaves will also help the plant store energy for next year's flowers.

Before cutting the stems, dip your pruning shears or secateurs in rubbing alcohol to lessen the chance of spreading disease. 

Simply cut back everything to about 1 inch above the ground, being careful not to damage the crown of the plant. 

'To promote healthy growth of peonies for the spring, cut back the foliage to ground level in winter to avoid the fungal disease peony wilt,' says plant expert Sarah Raven. 'Generally, peonies require very little pruning, but as with any shrub, it helps to maintain good overall health.'

If you find any buds near ground level, leave them. They are often referred to as 'eyes', and they are next year's stems. 

Make sure you get rid of any dead foliage carefully to avoid spreading fungal disease (botrytis blight or gray mold), which affects peonies and can survive the winter months in compost heaps.

When it comes to pruning tree peonies they respond well too. Prune in the fall and either take back the top growth by about a third in stages or, if you have a multi-stemmed tree peony, cut back every third stem to just under an inch (about 2cm). Start by removing the oldest stems.

Protecting peonies in cold weather

In fall, give your peonies a soil treatment before the winter months set in. 'You should begin by applying a thick layer of compost over your peonies, which will help insulate them from the elements and provide essential nutrients that will help them remain healthy throughout the winter,' says Mike Futia.

Known as mulching, this is key to getting the best out of your peony plants. 'Peonies planted in the ground should be mulched with a few inches of organic matter, such as compost or leaves, to protect their roots over winter,' says Miguel Palma, professional gardener and owner of JardinTienda.

You can also use straw, pine needles, or bark mulch for winterizing peonies. A good layer of mulch will prevent repeated freezing and thawing of soil that may heave and damage plants, and potentially stop peonies from blooming. In spring remove the mulch as soon as growth resumes. You can take a similar approach when wintering roses too. 

'You can also apply a winterizing fertilizer to the plant in fall,' says Zeeshan Haider, CEO and founder of GreenryEnthusiast.com. 'This will help provide additional nutrients for the plant to help it survive the winter. Be sure to follow the instructions carefully and apply the fertilizer in the appropriate amount.'

In areas with very cold winters, you may want to add an extra layer of cover for your peonies, especially if you want to protect plants from snow. 'Cover the plant with a layer of burlap or other fabric, and secure it with stakes or rocks,' says John Thomas of Backyard Garden Geek. 'This will help to insulate the plant and protect it from the cold.'

If you have tree peonies and live in a colder area, such as USDA zones 4 and 5, try wrapping the bush with burlap in late fall to provide protection against winds in addition to cold temperatures. 

Will peonies survive a cold and frosty winter?

Peonies are perfect for climates with cold weather seasons as they thrive best in the spring when they have had weeks of low temperatures during winter. 

'Peonies are winter hardy in USDA hardiness zones 3-8,' says horticulturalist and plant expert Brody Hall of The Indoor Nursery. 'This means they can survive very low temperatures, making them an excellent choice for gardens in cold climates.'

Sometimes peonies can suffer frost damage, according to the experts at the American Peony Society. 'This is visible through wilting stems in the morning but plants bounce back later in the day. Occasionally colder nights produce lasting damage exemplified by dead shoots, which do not recover. But more often than not, early shoot and stem loss is replaced with new growth from dormant eyes and buds.'