Tree peonies (Paeonia suffruticosa) are stunning ornamental shrubs prized for their lush, exotic blooms in shades of white, pink, red, purple and yellow While generally low maintenance, pruning is important for shaping, invigorating growth, and maximizing flowers on mature plants Follow this complete guide to learn when and how to prune tree peonies step-by-step.
When is the Best Time to Prune Tree Peonies?
Timing is key when pruning tree peonies. Do not prune in the fall or winter because frost could damage fresh cuts. The best time to prune is late winter or early spring, before new growth appears. This encourages strong regrowth and lots of blooms, though some early flowers will be lost. To avoid flower loss, prune plants right away when they stop flowering in early summer. But regrowth will be slower.
Tools Needed for Pruning Tree Peonies
Have these tools on hand before starting
- Bypass pruning shears for smaller stems
- Pruning saw or loppers for cutting thicker wood
- Garden disinfectant to treat cuts
- Garbage bags for removing debris
Always sanitize tools between cuts to prevent disease spread.
Step-by-Step Guide to Pruning Tree Peonies
Follow these simple tips to properly prune tree peonies:
1. Remove All Dead Wood
First, eliminate any dead, damaged or diseased stems. Cut these unsightly branches back to the base or original bud. This improves air circulation and form.
2. Cut Back Overgrown Stems
If your tree peony is overgrown or leggy, rejuvenation pruning is needed. Identify any wayward stems extending past the plant’s natural shape. Prune these unruly stems back to just above a healthy outward facing bud to encourage bushier regrowth within bounds.
3. Thin Out Excess Interior Growth
When tree peonies get too crowded, especially in the middle, their woody stems tend to grow into thickets. Some inner stems are cut off during thinning cuts to let more air and light in. Prioritize keeping younger, healthy exterior canes. Taking off one to two older stems from the inside of plants every year slowly improves crowded plants.
4. Shape and Control Size
Strategically trim wayward branches to keep the plant’s shape compact. By cutting back longer stems by at least a third of their length, energy is sent to lower buds. Cut back any offshoots that grow beyond the desired footprint to make the tree smaller.
5. Deadhead Spent Blooms
Finally, tidy up faded flowers. Cut off wilted flowers just above a healthy lower leaf with clean shears. Deadheading keeps plants looking their best. Collect seed pods in fall if desired.
Common Pruning Mistakes to Avoid
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Never shear or heavily prune tree peonies all at once – this can kill them. Take a gradual, minimalist approach over years.
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Don’t leave branch stubs – always cut back to a healthy outward facing bud.
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Avoid heavy pruning in fall when frosts begin – only remove dead wood once dormant.
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Prevent wounds or disease transmission by disinfecting tools between cuts.
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Don’t pull off dead leaves – carefully cut them to avoid stem damage.
With proper technique and timing, pruning will keep tree peonies thriving for decades with abundant flowers. Follow these tips for healthy, floriferous shrubs!
Grouping – 3 Plants
Small Hedge – 4 Plants
Fall planting occurs from late August until the ground freezes solid for winter.
As with all cold-hardy plants, fall is the traditional time to plant and historically the only time peony roots were available. Thus, typically peonies are shipped bare root in the fall. They are freshly dug, and should be planted immediately.
PEONIES ARE COLD-HARDY PERENNIALS. They should be planted the first chance you can get a shovel in the ground, regardless of frost or freeze potential. Do not wait for the frost date to plant your peony roots.
PLANT THEM AS SOON AS POSSIBLE. Utilize the day or so between cold periods, when the ground is thawed enough to dig. New peonies are susceptible to frost heaving; any peonies heaved out of the ground should be put back to their original location. If it is too frozen to do so, they can be covered in place with soil until the ground thaws or taken in and placed in peat moss in the refrigerator until the ground thaws enough to dig. Peonies need cold weather to flower in the spring, so don’t mulch them. Mulch will keep the peonies from getting cold.
Winter planting occurs from the time the ground freezes solid, until the time the ground starts to thaw.
Follow the same instructions for winter planting as you would for fall planting. Here are some additional tips for the winter months:
IF THE GROUND IS FROZEN SOLID at the time of purchase or delivery, it is best to store your peony roots in the fridge until you are ready to plant. Keep them in the bag as they came, do not add water.
PEONIES ARE COLD-HARDY PERENNIALS. Plant them the first day that the ground has thawed enough to get a shovel in the ground. Do not worry if the ground has the potential to freeze again, or if it will snow.
IF YOUR PEONIES HAVE SPROUTED, plant as above. Make sure to protect new shoots from frost, as they are more susceptible to frost damage if not planted the correct distance underground.
Spring planting occurs from the time the ground starts to thaw, through mid June.
PEONIES ARE COLD-HARDY PERENNIALS. They should be planted the first chance you can get a shovel in the ground, regardless of frost or freeze potential. Do not wait for the frost date to plant your peony roots. It is best to plant them while you still have cold or snowy days in the forecast.
If the ground is frozen solid when you buy or get your peony roots, it’s best to keep them in the fridge. Plant them the first day that the ground is soft enough to dig, regardless of future temperatures. Keep them in the bag as they came, do not add water.
If you plant peonies without their roots in the spring, they probably won’t grow much above ground the first year. You might find that the buds and leaves on peonies that were grown in pots die off before they are ready to be planted. Don’t worry, this is normal. That said, diseases are more prevalent on peonies that have been planted in spring. Watch for botrytis and treat accordingly.
There is an old adage when planting perennials: “First year roots, second year shoots, third year flowers.” Getting your peonies in in the spring gets a jump on things, giving your plant a good first spring of root development. Next year you are likely to have a reasonably sized peony with the potential of a flower or two.
The exact way to plant your tree peony depends on the root you received. Peony’s Envy typically sells 3-4 year grafts with ample roots (the middle ). Regardless, make sure you dig a very deep hole and plant your root very deep.
Plan for the plant to mature to 5 feet wide. See Garden Layout for more information
New tree peony plants should be planted 5 feet apart on center, and approximately 2.5 feet from any edge.
Start by digging a hole at least 2 feet deep and 1 foot wide. This will seem like a huge hole, but it is necessary for root growth and drainage. Your tree peony prefers to be planted and left in one location for generations, so it is worth taking the time to do it right. Amend your soil, as mentioned below.
Tree peonies should be planted deeply.
Grafted tree peonies should be planted so that the graft is six inches below the surface of the soil. This deep planting allows the tree peony to grow its own root system and prevents the grafted herbaceous root from growing herbaceous shoots. Any herbaceous shoots growing from a grafted tree peony should be cut back, and planting depth should be checked.
Tree peonies growing from their own root system should be planted so that the point at which the stems emerge from the root is two inches below the surface of the soil. This will promote additional branches to emerge from the root.
Once planted, press down on the soil to remove air pockets around the root and water your tree peony in well. During the first two growing seasons after planting a new tree peony, ensure that it gets a good soaking every two weeks. This will allow the plant to get enough water while the root system becomes established. Remember that peonies do not like wet feet and be careful to not over water. The soil needs to dry out fully between waterings. Watering daily or the use of foliar sprinkler systems can cause rot. It is essential that your peony be planted in well-draining soil so that the water does not pool around the plant. Established peonies are incredibly low maintenance and require little to no supplemental watering, except in times of extreme drought.
As your peony prefers to be planted and left in one location, it is worth taking the time to prepare the soil. Soil prep matters!
- It is best to have your soil tested before you plant new gardens. This is a link to the NJ Rutgers site that we use. If you are in a different state, please get help from your state’s agricultural extension office.
- You want to make a friable loam, which is a soft, rich, loose soil made of compost, clay, and sand. Peonies prefer a neutral pH of 6. 5-7. Most often, you are looking to raise the pH. You can do this by adding lime and/or wood ash. Ask your agricultural extension for help.
- Generally, most dirt is sand and clay. Be prepared to add compost. Sandy soils drain well, but nutrients are lost; heavy clay soils drain poorly, but nutrients are kept. Compost will help the soil drain better and keep water in, and it will also provide nutrition. Sprinkle a thin layer of compost on top of very sandy soil every three months. The nutrients will quickly leach through the soil. Heavy clay soils often have trouble draining. They will hold on to nutrients longer, but they will also hold on to water. So, before planting, you must improve drainage by adding Greensand (or sand/rock dust) and compost. Additionally, top dressing with compost is recommended.
Improperly planted tree peony. The blue arrow shows the herbaceous graft sprouting herbaceous stalks. This root was planted too shallowly. When the herbaceous root sends up stalks, it takes energy away from the tree peony and impedes growth.
The roots of a properly planted tree peony. The blue arrow shows the original herbaceous graft. The plant is growing a healthy fibrous tree peony root system above the graft.
We do not recommend planting peonies in pots, especially tree peonies. They do best when planted in the ground. Peonies are long-term perennials that will live for generations.
If you don’t have any space directly in the ground peonies can be successfully grown in raised beds. Drainage is the key to planting in any situation, especially raised beds. The beds need to be at least 2 feet deep to accommodate the deep planting necessary for tree peonies, see above. We line the boxes with landscape fabric and fill them with potting soil amended with compost, worm castings, and crushed limestone or granite. The beds are placed on the existing soil for optimal drainage.
If you have lots of experience growing other long term perennials in pots you may also have success with peonies but it is risky. Make sure your pot is large, more like a planter, is at least 2 feet deep and at least 5 gallons in size – the bigger the pot the better. Commercial potting mixes are available, we have yet to find one that we really like, look for those with extra porosity.
Containers will need to remain outside in the winter as peonies need the cold season to flower (do not bring them inside or store in a warm greenhouse). Be sure that your pots do not continually fill with water, as this will cause peonies to rot. Peonies are especially susceptible in winter when the bottom of the pot can be frozen and prohibit drainage if the weather switches to rain. This factor is easier to mitigate in warmer climates that get fewer extreme freeze thaw cycles.
We also do not recommend having peonies in pots for a few seasons and then moving them to the ground. Peonies should be planted originally in their permanent location. Moving them will cause undue stress to the plant.
The graphics below show growth expectations for tree peonies.
It is possible that a tree peony will not produce growth above ground or leaf out the first spring. This can be very scary but typically the tee peony will start to take off the following spring. Even it they do leaf out the first year, do not expect much out of your tree peony. Peonies are very resilient and hardy, but do take time to establish and become a mature flowering plant.
They follow the adage, ‘first year roots, second year shoots, third year flowers’.
Tree peonies should reach full height and size by year ten. The height, leaf coverage, and flower posture of your tree peony depends on the cultivar.
To choose the best cultivars for your particular garden, it is good to know more about the history and hybridization of each peony plant. This greatly influences how each cultivar behaves in the garden. These factors will also influence the bloom time. The main groups of tree peonies are, in order of bloom:
- Classic Tree peonies (Suffruticosa)
- Gansu Tree Peonies (AKA Rockii)
- Yellow Tree Peonies (Lutea hybrids),
We will review the characteristics of each type below, with suggestions on how to choose cultivars. We will start with the largest group, the classic tree peonies.
How to Prune a Tree Peony
FAQ
Should tree peonies be cut back?
If you want to change the shape of your tree peony or make it smaller, cut back a few stems to new buds at or near the ground (15 cm).
Do tree peonies bloom all summer?
There are very few plants that can compete with a tree peony in full bloom. They flower from late April to early May, but the season can often vary from year to year. We just started to see these beautiful flowers open up last week. The petals are so soft and pretty.
What is the difference between a tree peony and a peony?
Tree peonies are actually small shrubs, rather than trees, producing gorgeous, goblet-shaped flowers in May and June. Herbaceous peonies lose their leaves every year, but tree peonies stay tall and have a structure all year.
Do tree peonies need to be pruned?
Tree peonies can take time to become well established so new plants are best left untouched for the first couple of years. After that, they require very little pruning beyond deadheading and the removal of any dead wood. Use a pruning saw or loppers and a sharp pair of secateurs. In summer, deadhead the flowering shoots once the flowers have faded.
How do you prune peonies?
Begin by gently cutting back the stems to about 2 inches above the soil level. Remember, these precious peonies have been through a lot during their growing season, so be gentle and considerate when you prune back. Dispose of the pruned foliage to prevent potential overwintering of pests and diseases.
When is the best time to prune peonies?
Yes, fall is the perfect time to prune your herbaceous and Itoh peonies. When your plants start to show these signs of wilting and yellowing foliage, it’s time to get your pruning shears out. Here are some expert tips for cutting back your peonies in the fall.