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Peonies 101: How to Grow Herbaceous Peony Plants
Impressive blooms up to 25cm will delight any gardener
Part of our Spring Flowering Plants guide: By Daniel Woodley at DIY Gardening
Flamboyant, sumptuous, bold. These are just three of many words one can use to describe peonies which are, in our opinion, one of the best late spring/early summer plants for beginners and competent gardeners alike.
There are three types of peony to consider:
- Peony trees: These are woody and live up to 90 years.
- Herbaceous peonies: Are more fragile and die back to ground level each year, then reappear the following spring.
- Intersectional peonies: These are a hybrid of the two but are less common.
All three peonies produce large blooms, which make perfect cut flowers.
This growing guide covers herbaceous peonies, the most popular variety.
Size
Herbaceous peonies grow to:
Height: Up to 1m (3′)
Width: Up to 1m (3′)
Type
Deciduous: Dies down to ground level in the winter
Growth
Herbaceous peonies reach maturity after three to five years and regrow from their roots each spring
Difficulty
Moderately difficult to grow and maintain
Native
China, Siberia
Location
Sheltered from the wind in a spot with good air circulation and in rich but well-drained soil
Sunlight
The more sunlight, the more flowers you can expect so plant in full sun or in a spot that gets at least 8 hours per day
Hardiness
US zone 3-8 and hardy in all parts of the UK
Water & Feed
Water deeply once a week in the summer but never let them sit in soggy soil. In fertile soil, there is no need to top up with fertiliser; otherwise, add organic matter or slow-release fertiliser
Companions
Hydrangea, azaleas, iris, rhododendron, lilac, alliums
Planting
Plant when the soil is warm in autumn or spring
Flowering
Typically in May and June but sometimes into July as well
Peony Growing Guide: Answers to Common Questions
How and When are Peonies Sold?
Peonies are sold as bare-root plants in autumn or spring or as established plants in late spring/early summer.
Bare root plants are best, although if you’ve missed the best planting time, go for established plants which are often sold in pots in garden centres.
Where is the best location for peonies?
Peonies prefer a sunny spot but will tolerate light shade, although often at the expense of bloom size and number.
They perform best when given some space and air circulation but should be grown in a relatively sheltered spot away from strong winds which could snap the stems.
How should the soil be prepared?
Prefers fertile soil that’s free draining so dig in grit and/organic matter to improve the ground conditions if required.
The bare roots shouldn’t be overwatered – this is a common cause of root rot.
The planting depth is crucial – peonies may not flower if planted too deep. The crown should be no more than an inch below ground level, any lower and it may not flower or may not even grow at all.
Do peonies require lots of water or fertiliser?
Peonies thrive in free-draining soil and dislike soggy ground conditions. There’s no need to overwater them and while a slow-release fertiliser can be used, a better option would be to dig in compost or rotted manure once a year to improve the soil.
How tall and wide will peonies grow?
Herbaceous peonies usually grow to just under 1m tall and 1m wide (3′ x 3′).
Should peonies be pruned and deadheaded, and if so, how and when?
Peonies should be deadheaded as soon as the flowers fade and before the seeds have set.
Allowing the seeds to set will affect next year’s blooms, and not in a good way!
The foliage should be left in place until the autumn so energy can be sent to the roots, making them stronger for next year.
As for pruning, peonies should be cut back to ground level after the first frost.
Do peonies suffer from any pests and diseases?
The most common disease affecting peonies is powdery mildew on the leaves, but this can be remedied by growing the plant in a spot with good circulation and plenty of sunlight.
Any affected leaves should be removed rather than allowed to accumulate on the soil, and the gardeners should avoid overhead watering, which spreads fungal spores to nearby leaves.
Peony wilt is a similar fungal infection with no known cure; find out more about this on the RHS website.
Slugs and snails may attack young shoots but generally back off once the plant has matured.
Slug repellants may be used for a month or two but shouldn’t be required all season.
Root worms may attack the roots, but beyond this, peonies are generally pest resistant.
When do peonies bloom and how long for?
Herbaceous peonies bloom in late April, May or June, depending on the variety and the climate.
Peonies are infamous for their short flowering period, often no more than 10 days but this depends on the climate and the amount of and intensity of the rain, which can turn the blooms slushy.
Can peonies be propagated?
The best way to propagate peonies is by root division in the autumn, just after the plant has been pruned to ground level.
Just follow these steps if you want to grow more plants:
- Wait until autumn and prune off the stems to a few inches above ground level.
- Carefully dig up the rootball which could be large and deep.
- Wash the soil from the roots with a hose.
- Using a sharp knife, cut off root sections making sure each has a minimum of three buds and plenty of root material.
- Replant straight away in the garden.
Are peonies toxic or harmful to humans and pets?
All parts of the peony are toxic to pets and humans.
Are peonies beneficial to wildlife?
Peony flowers attract ants, but they don’t cause any harm to the plant.
Single peonies attract bees, but according to this forum chat, bees usually prefer other plants.
Can peonies be grown in pots?
The roots of peonies can grow very large and deep and aren’t suited to small or medium-sized pots.
Even peonies grown in larger containers will need to be lifted after a few years and replanted.
In general, yes peonies can be grown in pots but for no more than a few years.
Growing Peonies: 10 key Points
Here are 10 key points anyone growing peonies should consider:
- Peonies can take a few years before they produce blooms, so if possible, buy strong, large bare roots which are established enough to bloom in the first year.
- Never plant peonies in soggy soil where water pools.
- Add grit and organic matter to improve the soil conditions.
- Don’t overwater the bare roots after planting; they dislike excess moisture and will do just fine in well-drained soil.
- Protect peonies from strong winds by locating them in a sheltered spot or using supports, stakes or a frame. The stems of peonies are weak and liable to break, so care should be taken to protect them.
- There’s no need to douse peonies with fertiliser every week, just top up the soil with some organic matter once a year or dig in a slow-release feed once a year, in the spring.
- Watch out for leaf mildew or other signs of disease on the leaves. If possible, aid air circulation, avoid overhead watering and clear away fallen leaves promptly.
- Deadhead after flowering but leave the foliage in place until well into autumn.
- Prune to a few inches above ground level in the autumn, around the time of the first frosts.
- Prune, dig up, divide and replant to propagate if required. This is best done in the autumn.
How to Grow Huge Peony Flowers
As with many plants, the size of the flowers on peonies can be determined by the gardener via selective pruning.
The process is simple; by pruning off stems, the plant will send its energy to the remaining flowers, making them grow bigger.
The gardener can choose to cut off lots of stems, leaving only a few large blooms, or no branches can be pruned, leaving more numerous but smaller flowers.
Another plant that responds well to selective pruning is dahlias.
We published a guide to growing big dahlia flowers last year and many of the tips we suggested apply to peonies too.
Recommended Peony Plant Varieties
There are dozens of peonies to choose from, but here are our favourites:
Sarah Bernhardt Peony is a popular variety growing to 1m and producing large fragrant double blooms. A reliable bloomer that puts on a show in June and sometimes into July.
Bowl of Beauty is another popular peony, growing to 90cm and producing pink cupped blooms up to 25cm. You’ll love the powerful fragrance of this variety too.
Chocolate Soldier is an upright, clump-forming peony delivering dark red/maroon flowers complimenting the dark green foliage.
Peony Companion Plants
Some gardeners plant low-growing spring bulbs (such as crocus and snowdrops) at the base of peonies and these fade just as the peonies come into bloom.
Another option is to mix mid-size shrubs around the peonies, leaving just enough space for air circulation.
Consider these plants as they make for great companions for peonies:
Common Peony Plant Problems
Peony plants are tough and require little care and attention once established if grown in suitable conditions, but as with any plant, there are a few common problems:
1) Peonies Not Flowering
This is usually caused by one of the following:
- The plant is still young and isn’t mature enough to produce blooms. Peonies need up to three years of growth before they can bloom, hence why gardeners should buy from reliable growers.
- Too much shade – established peonies should bloom profusely; if they don’t, it could be due to a lack of sunlight.
- Too much water – peonies dislike soggy soil and may refuse to bloom at all if grown in wet soil.
2) Ants on Peonies
This is normal, the ants are attracted to the flowers, and they actually help to open them, after which they will disappear. There is no need to take any action as the ants won’t harm the peonies.
3) Grey, Mouldy Stems and Weak Leaves
This is most likely due to one or more the following:
- Fungal disease.
- Overhead watering.
- Lack of air circulation.
- Diseased leaves are not being cleared away.
- Poor sanitation of garden tools, including secateurs, spades etc.
Hannah’s Peony Pro Tip
Here is a quote from Hannah, our co-founder:
Peonies can take up to three years to establish themselves and produce blooms so don’t be tempted to buy cheap, small plants; you could have a long wait!
Spend a little more and buy from reliable growers who shouldn’t be selling young plants.
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More From Daniel Woodley:
This guide to growing peony plants for late spring and early summer colour was created by Daniel Woodley here at DIY Gardening and was last updated in February 2022.
Discover more spring-flowering bulbs and plants here.
Daniel is a keen gardener who also manages a large residential landscape in addition to his own mid-size garden.
He also enjoys experimenting with vegetables and fruits in his garden but with varying success!
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