Peonies are one of the most beloved perennials in many gardens, and for good reason.
Their large, fluffy blooms, rich colors, and delightful fragrance make them a showstopper in spring and early summer.
However, as the temperatures begin to drop in September, it’s important to start thinking about how to protect your peonies through the cold months.
Over the years, I’ve learned that the steps you take in September can greatly influence how well your peonies survive the winter and how they thrive next season.
It’s a time to clean up, protect, and prepare your plants for dormancy so that they’ll return healthy and vigorous next spring.
Here’s what I do to ensure my peonies come through the winter strong and ready to bloom.
Assess the Health of Your Peonies
Before diving into any pruning or mulching, it’s a good idea to assess the overall health of your peonies.
Take a walk around your garden and inspect each plant for any signs of disease, pests, or damage.
Are the leaves looking healthy, or are they yellowing, blotchy, or wilted?
Check the stems for any signs of rot or weakening.
By catching problems early, you can take action to stop them from getting worse during the winter.
In my garden, I often see yellowing or browning leaves in late summer, which is completely normal as peonies naturally begin to go dormant.
However, if I notice black spots or mold, I know I’m dealing with a fungal issue like botrytis blight, which needs to be addressed immediately.
When you spot any diseased or damaged foliage, removing it before winter will help prevent the disease from spreading and overwintering in your garden.
Cut Back Peonies in Late September
One of the most important tasks for ensuring your peonies survive the winter is cutting back the foliage in September.
Once the leaves have yellowed or browned, the plant is done photosynthesizing for the season and is preparing for dormancy.
This is the perfect time to trim back the leaves and stems to prevent diseases and pests from finding a cozy winter home in the foliage.
In my own garden, I’ve found that cutting back peonies to about 2-3 inches above the ground in late September works best.
I use sharp, clean pruning shears to make clean cuts just above a healthy bud or stem joint.
Removing all the dead foliage is key to preventing fungal diseases from overwintering and reemerging in the spring.
I’ve made the mistake of waiting too long to cut back peonies before, and it led to more issues with rot and pests the following year.
After pruning, I always dispose of the cut leaves and stems in the trash, not the compost pile, to avoid spreading any potential disease.
This step is crucial for keeping your garden healthy year after year.
Don’t Over-Prune—Leave the Eyes Intact
While cutting back the foliage is essential, it’s important not to prune too aggressively.
Peonies form their buds, or “eyes,” for next year’s growth at the base of the plant, just below the soil surface.
These eyes are delicate, and if you accidentally cut them off, you’ll lose next year’s blooms.
So, as you cut back the foliage, be careful not to disturb the crown of the plant where these eyes are located.
In my garden, I always take extra care to leave the base of the plant untouched, as this is where the peonies will regrow from in the spring.
If you’re unsure where the eyes are, gently brush back the soil around the base of the plant to see them—they’ll be small, reddish buds clustered at the crown.
Once you spot them, you’ll know to avoid cutting too close.
Clean Up the Garden Bed
After cutting back the foliage, it’s essential to clean up the area around your peonies.
Any leaves, stems, or plant debris left on the ground can harbor diseases and pests over the winter, which can infect your plants when they start growing again in the spring.
I’ve learned that a clean garden bed is one of the best defenses against common peony issues like botrytis blight, which thrives in damp, cluttered areas.
I use a small rake or my hands to gather up all the debris around the peonies, making sure to remove every last bit of dead material.
This is also a good time to check the soil for any signs of pest activity, such as tunnels or disturbed soil, which could indicate problems like voles or grubs.
In addition to cleaning up plant debris, I sometimes like to loosen the top layer of soil around the peonies with a hand cultivator.
This helps aerate the soil, improving drainage and reducing the risk of water pooling around the roots, which can lead to rot.
Apply a Protective Layer of Mulch
Mulching is one of the most important steps for ensuring your peonies survive winter, especially if you live in a colder climate where temperatures drop below freezing.
Mulch helps insulate the roots and crown of the plant, keeping the soil temperature more stable and protecting the delicate buds from extreme cold.
I typically apply a 2-3 inch layer of organic mulch, such as straw, shredded leaves, or compost, around the base of my peonies after I’ve cleaned up the garden bed.
It’s important to avoid piling the mulch directly on top of the plant’s crown, as this can lead to rot.
Instead, spread the mulch around the plant, leaving a small gap around the base to allow for air circulation.
Mulching also helps retain moisture in the soil during the winter and prevents weeds from growing, which is always a bonus.
In my own garden, I’ve found that mulching in September gives my peonies the protection they need to weather even the harshest winters without any issues.
Stop Fertilizing in September
It’s important to stop fertilizing your peonies in September, as they’re getting ready to go dormant for the winter.
Fertilizing at this time can encourage new growth, which won’t have time to harden off before the first frost, making the plant more susceptible to winter damage.
In my experience, fertilizing peonies in the early spring, right before they start actively growing, is the best approach.
By giving them a boost of nutrients in the spring, you help them grow strong and produce those gorgeous blooms, but in September, it’s best to let the plant naturally wind down for the season.
If you feel like your soil could use a bit of nourishment, you can add a light layer of compost around the base of the plant when you mulch.
Compost will break down slowly over the winter, enriching the soil without overstimulating the plant.
Water Sparingly in the Fall
As September progresses and temperatures start to cool, you’ll need to adjust your watering schedule.
Peonies don’t need as much water in the fall, especially as they begin to go dormant.
Overwatering at this time can lead to soggy soil, which increases the risk of root rot, particularly if you live in an area that gets heavy fall rains.
I usually reduce my watering in September, only giving the plants a deep soak if the soil is extremely dry.
By the end of the month, I stop watering completely unless we experience an unusually dry spell.
Allowing the soil to dry out slightly before winter can help prevent issues like crown rot, which can occur if the roots sit in wet soil during cold weather.
Check for Pests and Disease
September is a good time to give your peonies a thorough inspection for pests and diseases before winter sets in.
While peonies are generally hardy plants, they can still fall victim to issues like aphids, spider mites, and fungal diseases like botrytis blight.
In my garden, I’ve had a few run-ins with botrytis blight, which shows up as blackened, mushy areas on the stems and leaves.
If you spot any signs of disease, prune off the affected areas immediately and dispose of them in the trash.
Be sure to clean your pruning tools afterward to prevent spreading the disease to other plants.
For pest control, I’ve found that a strong spray of water can often knock aphids or mites off the plant.
If the infestation is more severe, I’ll use insecticidal soap or neem oil to treat the problem.
Divide Overgrown Peonies
If your peonies have been in the same spot for several years and seem to be producing fewer blooms, it may be time to divide them.
September is the perfect time to divide and transplant peonies because the plants are starting to go dormant, which minimizes stress on the roots.
Dividing peonies can rejuvenate the plant and encourage more vigorous growth and flowering.
I usually dig up the entire root ball carefully, using a garden fork to lift the plant without damaging the roots.
Once it’s out of the ground, I use a sharp knife to divide the root clump into sections, making sure each section has at least 3-5 healthy eyes.
After dividing, I replant the peony divisions in a new location, making sure to plant them at the same depth as the original plant.
Water them well, and they’ll settle in nicely over the winter, ready to produce beautiful blooms next spring.
Don’t Worry About Frost
Peonies are hardy plants that can tolerate frost, especially once they’ve gone dormant.
If you live in a region with mild winters, your peonies will likely be just fine without much extra protection.
However, if you’re in an area that experiences heavy frost or freezing temperatures, mulching is your best defense to help insulate the roots.
I’ve learned that it’s important not to panic when the first frost hits—peonies are built to handle cold weather.
As long as you’ve taken the necessary steps in September, your peonies should come through winter without any trouble.
Plan for Spring Success
Everything you do in September sets the stage for a successful spring.
By cutting back the foliage, cleaning up the garden bed, mulching, and protecting against pests and disease, you’re giving your peonies the best possible chance to thrive next season.
In my experience, peonies respond beautifully to this fall care routine, emerging in the spring with healthy foliage and a bounty of blooms.
It’s rewarding to see them return year after year, knowing that a little bit of effort in the fall makes all the difference.
Final Thoughts
Taking care of your peonies in September is essential for ensuring their survival through the winter and setting them up for a successful growing season next year.
By following these steps—cutting back, cleaning up, mulching, and monitoring for pests—you can protect your plants from the cold and help them store the energy they need for vibrant growth in the spring.
From my own experience, I’ve learned that peonies are incredibly resilient when given the right care.
With just a little effort in the fall, you’ll be rewarded with stunning blooms and healthy plants for many years to come.
Happy gardening!