Pruning tree peonies: simple tips for these gorgeous blooms

Pruning tree peonies is the best way to ensure you'll see plenty of lovely blooms each year. 

These woody-stemmed shrubs produce large flowers in the spring, thanks to their stems not dying back over winter like herbaceous peonies do. However, if you don't prune the tree peony stems from time to time, there's a chance they'll get leggy over the ensuing years and won't have as profitable a growth. 

Even beginner gardeners can learn how to care for these types of peonies, though. The tree peony actually does well with a bit of neglect!

Top tips for pruning tree peonies

Luckily, when it comes to how to prune tree peonies, there's little effort required. The main tasks you need to accomplish are deadheading the spent blossoms, and removing any dead wood by cutting back to a healthy bud.

John Negus of Amateur Gardening magazine tells us to use your best secateurs, pre-sharpened, to remove the tree peony’s faded blooms. 'If you leave a plant to produce seeds, energy is channelled away from strong new growth,' he says. Make your cuts just above new growth.

You can also cut a few stems back to ground level if you'd like to reduce the size of the tree peony. Leggy stems can be cut back by a third, adds the RHS.

'After pruning, feed with a general fertilizer, such as fish, blood and bone meal, Vitax Q4 or Growmore,' says John. Additionally, he suggests nourishing your plant, monthly, until early fall, with flower-inducing sulfate of potash. 'Sprinkle it at 1oz (28g) per square meter around the plant and water it in.'

When should you prune a tree peony? 

If you're cutting back woody stems, John Negus says, 'The best time to prune a tree peony is in early spring. Any later and it may bleed, which will weaken it. Admittedly, you will have to sacrifice some of its enchanting blooms, but it will be easier to manage.'

Deadheading flowers can be done in the summer, or, as the RHS says, in autumn if you wish to collect the seeds first.

Tree peonies grow rather slowly, producing only a few inches of woody growth each year. With that in mind, avoid pruning in the first couple of years to allow the plant to establish itself – and wait to plant them in either spring or fall so they don't have to experience any intense summer heat. 

How to get a peony tree to bloom 

The best conditions for a tree peony are protection from winds, relatively dry soil and some dappled shade in the afternoon. They also need good drainage to avoid becoming waterlogged.

Sometimes, there might be issues with a tree peony producing flowers. If your peonies are not blooming, try cutting a few old stems back to ground level to encourage more growth. You also may have planted the peony too deep. In which case, wait until the dormant season in fall and gently replant at less depth.