Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
Contributions From CAROL ADELMAN
Not only is she the President of the Pacific Northwest Peony Society, but Carol is also the owner of her own plant nursery, Adelman Peony Gardens. Having been awarded ‘Best of Show’ at 9 of the last 15 American Peony Society shows, Carol has also had a book published about peonies.
IN THIS GUIDE
Peonies are attractive, traditional cottage garden plants that can (contrary to some opinions) grow well in suitable pots.
However, as deep-rooted plants, peonies do require deep pots or containers.
They will be more challenging to grow in pots than in the ground.
Remember, peonies are large and vigorous plants – and as with so many other plants, it will be far easier to grow them in beds or borders.
But, you can still grow them in large pots if you are lacking in outdoor space.
Potted Peony Varieties
Some peonies which are better suited to growing in containers include:
- Paeonia ‘Oslo”
- P. ‘Singing in the Rain’
- P. ‘Dublin’
- P. ‘Moscow’
- P. ‘Border Charm’
- P. ‘Bartzella’
- P. ‘Gay paree’
- P. ‘Magical Mystery Tour’
Choosing Pots For Peonies
According to Carol Adelman, President of the Pacific Northwest Peony Society, providing plenty of space for peonies to grow is one of the most important factors when caring for these plants.
“Provide plenty of space for their growth. The roots grow out to the sides.
“Think of going to market and finding carrots with the tops on, then setting them down, all spread out in a circle.
“That is how a peony root grows – out every side.”
It is therefore best to start off peonies in a large pot that is at least 50cm deep and 50cm wide.
As your peonies grow, however, you will of course have to think about transferring it to a larger container.
It is likely that you will have to increase the container size every 3-4 years.
Be sure to choose a pot which is able to drain freely, as peony tubers can rot in waterlogged conditions.
Ensure that there are plenty of drainage holes in the base and that water can flow out of these freely.
Filling Your Pots
Peonies need a fertile and free-draining growing medium.
A general-purpose peat-free compost or potting mix, ideally mixed with topsoil or loam-based, should be amended with horticultural grit or perlite to improve drainage.
Remember that it will be important to keep the soil evenly moist throughout the growing season, but not boggy.
Make sure you leave 2.5cm space as a minimum for water at the top of the container, above the growing medium and mulch which should be added on top.
Siting Peonies In Planters
Peonies in pots should be positioned in a sheltered spot, in full sun or partial shade.
It is very important to think about how you will keep the plants protected from strong winds.
And you should also be sure to think about the ease of watering when choosing where to place plants in pots.
It can also be a good idea to consider other plants which bloom concurrently and which could look good grown in pots close to peonies in containers.
Irises, Lavender, Salvias and Alliums are all good options to consider, for example.
Roses might also be grown in pots close by.
Planting Peonies In Pots
Peonies are usually purchased either as bare-root specimens, to be planted out in late autumn, or as potted plants which are purchased and repotted in the spring.
When planting peonies in pots, it is very important to plant them to the right depth.
The crown of the plant should be no more than 2.5-5cm below the soil – planting too deep can reduce flowering.
Be sure to mulch after planting with well-rotted organic matter. A homemade compost or well-rotted manure can work well.
This mulch will add slow-release fertility, and prevent excessive evaporation from the soil surface, helping to reduce water needs.
Be sure to leave a clear space around the crown and developing buds as these may otherwise be damaged or begin to rot.
Potted Peony Care
Caring for peonies in pots or other containers is not always easy.
However, it can be relatively straightforward as long as you bear the following in mind:
Support
Some peonies benefit from staking, since they have larger flower heads and can sometimes struggle to hold these up without some support.
Be sure to place supports in your pots when planting if these will be required for the cultivar or cultivars you are growing.
Watering
Peonies grown in the ground will typically require regular watering in dry weather over the first year as they become established – but they will not usually require regular watering in the UK on an ongoing basis.
However, things are a little different when peonies are grown in pots, since containers will dry out far more quickly, and peonies’ deep roots will not be able to delve deep to seek out water.
Though peonies like free-draining conditions and are relatively drought-tolerant, it is important to keep your growing medium moist throughout the growing season when growing peonies in pots.
Feeding
As well as providing a good quality organic mulch around your plants, you should also feed your peonies in pots at least once a year in spring with a good quality organic fertiliser.
Experts suggest applying a spring peony fertiliser with an NPK of 10-4-18 (+ 2% MgO + 4% CaO).
It can also be a good idea to feed peonies again after summer flowering with a fertiliser with an NPK of 11-5-12 (+1%MgO + 3%SO 3).
However, making your own organic liquid feeds (such as compost teas etc.) with less precise or scientific formulae can still yield good results.
Deadheading & Cutting Back
Most peonies are hybrids and do not set viable seed, meaning any seed that did set would not come true.
So you will lose nothing by removing all dead flower heads after they have finished blooming.
When the peony foliage dies back in autumn, it is best to cut the foliage at ground level.
This should reduce the risk of peony wilt disease taking hold, which is a fungal infection – the main disease which impacts these plants.
Winter Care
Peonies tubers are usually left in the ground to overwinter in the UK when grown in beds and borders. They are fully hardy.
However, when you are growing peonies in containers, they can be more vulnerable to freezing.
They can also encounter problems with waterlogging over the winter months.
If you would prefer not to unearth the tubers, you can protect pots with insulating materials wrapped around the sides and mulches over the top.
Grouping containers together, and placing them close to materials (like stone or brick walls) or using pots with high thermal mass can also help prevent freezing.
And placing the pot undercover or in the rain shadow of a wall can help reduce waterlogging issues that can lead to rot.
You could also move the container (or just the tubers) into a cool space for overwintering, before repositioning or replanting them in spring.
Division
Peonies are long-lived plants and grow steadily.
Over time, they can make large clumps, and after potting up over the years, you may find that they outgrow the largest suitable container which is practicable.
Dividing mature peonies in late autumn will allow you to split your plant and repot sections into smaller containers, as well as giving the plant a new lease of life and boosting the blooms which may have begun to decline in number over time.
New plants from divisions will be clones of the parent plant and they should bloom after a couple of years.
“Division will be particularly important with container-grown plants because of the limited root environment,” shares Master Horticulturist Colin Skelly.
“Division will keep the plants rejuvenated and provides the opportunity to refresh the compost at the same time.”
Though growing peonies in pots can be a challenge, you may find it worthwhile to be able to enjoy these blousy, colourful blooms in your container garden.
See our full peonies care guide for tips on planting them in the ground.
