Peonies are reliable flowering perennial plants and last for many years yet there is so much misinformation about how to successfully grow them. Should we worry about ants on the buds? Why do some buds not open? Let’s go through the top tips and myths so you can grow these gorgeous flowers in your garden.
Crazy about hollyhocks? See 6 Tips for Growing Hollyhocks and Dealing With Rust.
Growing Peonies (Paeonia)
If you want a beautiful flowering perennial that lasts for years—some as long as 50 or 100 years—peonies are my top pick.
The peony—pe·o·ny (pēˈənē) (pronounced pee-uh-nee in most regions) is a spring-flowering plant, flowering for a few weeks in May or June.
Once established, a peony can provide flowers every year for decades with little or no maintenance.
If the crown (where the buds are produced) becomes really large, it is recommended that you divide it every few years. Other than that, there isn’t much to do but enjoy the flowers. I’ve provided specific tips below.
Three Types of Peonies
1Herbaceous Peonies (most are P. lactiflora)
These are the most common peonies and grow as bushes.
They die back to ground level each fall and re-emerge with red-tinged stems in spring, which garden designer Gertrude Jekyll deemed ‘dear rosy snouts’.
Years ago these herbaceous peonies were also called ‘piney’ peonies.
There is a database to help identify your peony at peonies.org.
Tree peonies grow as shrubs with woody stems. The leaves drop in fall but the stems remain.
We call them trees but they are really woody-stemmed perennials.
3Itoh or Intersectional Peonies
A hybrid of herbaceous and tree peonies, Itoh or intersectional peonies are prolific bloomers.
The stems are not as hardy as tree peonies.
The name Itoh comes from the grower Toichi Itoh in Japan who first managed to successfully cross tree and herbaceous peonies.
Frequently Asked Questions
These tips apply mainly to herbaceous peonies but I have included a few tidbits about tree peonies as well.
Read them all the way through and you will have an excellent understanding of how to successfully grow peonies.
1Will Ants Harm My Peonies?
No. Ants on peonies are harmless.
When peony buds are forming, nectar is present in the green sepals surrounding the buds.
This nectar is attractive to ants.
Once the flower opens and the nectar is gone, the ants go away.
Never use insecticides. The ants are just being ants.
2Is Transplanting Harmful to Peonies?
No. For years we have been told that peonies do not like to be moved and may not recover if we transplant them.
But that is not the problem.
The issue is failing to provide the basic necessities.
This is what peonies need:
- Sunny location | At least 6 hours of full sun per day.
They can still flower with less sun but this is optimal. With less light, blooms may be fewer, smaller, leggy, or delayed.
- Correct planting depth | See more on this below.
- Good soil | Moist, fertile soil with good drainage.
- Right climate
–Herbaceous peonies are suited to zones 2 to 8, depending on the cultivar and need a nice, long dormant period in winter followed by a humid summer for maximum flowering.
–Tree peonies are less hardy and do not require the same low temperature lows.
Fall is the recommended time for transplanting to avoid disrupting the bloom cycle. Personally, I move plants any time, careful to disrupt roots, buds, and tubers as little as possible.
Peony Planting Tips
Herbaceous peonies have tuberous roots with buds that become the stems and flowers.
The top bud on the tuber should not be planted more than 2cm (1-inch) below the soil surface.
Lack of adequate light and planting too deep can each limit or halt blooming.
Tree peonies are grafted and the graft should be planted 4-6 inches (10-15cm) below ground level.
3Help! My Peony is Not Blooming!
My Peony Has Very Few Blooms
There can be several reasons why a peony will not flower or produces few blooms.
First, is this a new problem? Has the plant flowered previously in the same location and growing conditions?
Or, is it a newly planted peony that has never bloomed?
These next questions will help you diagnose the problem.
1Does the plant look healthy?
Black or darkened stems are caused by a fungal infection (botrytis) also known as gray mold, triggered during cold, damp spells.
If that is the problem, you need to cut back the plant and dispose of it.
If the plant appears healthy but is not flowering, these next questions will help.
2Was it planted at the correct depth?
Planted too deeply, peonies will not bloom. See the recommended planting depths here.
3Does your peony get at least 6 hours of full sun each day?
Too little sun and the buds may never open.
4How recently was it planted?
Some peonies take a few years to get established before they will bud and bloom. If started from seed, the wait will be even longer.
5Is it an older plant that may need fertilizer?
A peony growing in the same location over many years may use up the available nutrients in the soil and need fertilizer.
Peony Societies recommend an organic 12-12-12 fertilizer applied according to the product instructions. This is usually done twice a year: once in spring and then again in late summer.
6Did you over-fertilize?
Exposure to excess nitrogen can over-stimulate leaf growth at the expense of flower production.
7Is another plant competing for root space?
Are other nearby deep-rooted plants like trees or shrubs crowding your peony?
8Did you have a late frost that may have killed the buds?
A late frost can kill the buds—referred to as bud blast, leaving them frozen in time or causing them to rot and drop off.
Related: Why Your Clematis Is Not Blooming
4Should I Deadhead My Peony?
With herbaceous peonies, deadheading is optional for cosmetic reasons but necessary if you want to prevent seed production.
Deadheading (snipping off the old flowers and their stems down to the first leaves) removes the seed pods and allows the plant to put its energy into additional root growth instead.
Many gardeners (like me) do not deadhead their peonies and growth is still fine.
Related: How to Deadhead Flowers
5Should I Cut Back My Peony in Fall?
Herbaceous peonies: Yes, you can cut back the foliage to just one inch above ground in fall after first frost. I do not cut back any of my garden in fall and by spring the old peony foliage has vanished.
Tree and Intersectional (Itoh) peonies: No, these are basically maintenance-free.
You can also mulch any of your peonies for added winter protection but be sure to remove the mulch in early spring, otherwise the buds may not get adequate heat for blooming.
Related: Fall Gardening Checklist
6Can I Grow Peonies in Containers?
Yes. Provide a nice, big container (at least 18-inches in diameter) and they can last for many years in pots. Some gardeners have kept their peonies in pots for over 20 years.
The only situation where I would hesitate is in a really cold climate.
The main concerns for container growing are adequate nutrition (fertilizer) and winter storage, to avoid freezing the roots.
Related: How to Grow Vegetables in Containers
7Do Deer Eat Peonies?
Only if there are few other options. Both deer and rabbits are not peony fans and would rather eat other things in your garden. If they can’t find anything else, they will eat the shoots rather than starve but given a choice, they prefer other plants.
8What’s the Best Way to Propagate Herbaceous Peonies?
Propagation by division can yield several, identical new plants. This is the fastest and easiest way to propagate peonies.
To divide (or move) a peony:
- Soak the soil the day before to make digging easier.
- Dig at least 2-feet out from the plant to minimize root damage.
- Have a large container of warm water ready to soak the tubers and roots.
- With a clean knife, slice sections with at least 5 eyes each (future buds). Each section will become a new plant.
- Plant each new plant in a sunny location at the right depth with ample room for root growth as described above.
Peony trees can be propagated by hardwood cuttings.
Saving Peony Seeds
Unless you deadheaded, your peony flowers will produce seeds in pods. I just leave them as-is every year but you can also try to propagate them.
If your peony is a hybrid, the seeds will not be true to the parents, but could still be viable. If you want a new plant just like the parent, you should buy one or divide one.
I have not tried germinating peony seeds but this is my understanding of how it works.
Seeds appear black if fertilized and may be viable. Red seeds are neither.
It is recommended to sow the seeds right away in fall. I assume this is because they do not store well.
If can take a year for peony seeds to germinate and they need two chill periods (cold winters) with a warm spell (summer) in between to get started.
Flowering may take as long as five years after initial germination.
9How can I keep my peonies from flopping over?
Some varieties have big flowers and narrow stems which makes them doomed to be floppy.
While you can’t change the genetics of the plant, you can put supports in place at the start of the growing season to greatly improve the appearance.
Metal grow-through plant grids are one option. Placed on supports, the peony stems grow through the grid holes, offering nicely-spaced support for the plant.
The traditional option is peony cages although they only provide outer support and do not distribute the stems as nicely as the grids do.
10Can I Use Peonies as Cut Flowers?
There are two options.
Either take flower cuttings (the flower with a section of its stem) as they come into bloom for immediate display or take bud cuttings while they are still closed and round but slightly spongey.
Bud cuttings should be wrapped in newspaper and chilled in the refrigerator. With proper storage, they can be kept for weeks or months before using in floral arrangements. The buds will open at room temperature when their stems are placed in water. I have not tried this so you may want to research more specific tips before trying it.
11I Am Crazy About Peonies: Where Can I Learn More?
National Peony Societies
You can also find state and provincial groups at these sites:
~Melissa the Empress of Dirt ♛