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If you have a tree peony, it requires very minimal pruning which is the good news. Still, it’s important to know how and when to prune your tree peony, just to make sure you get it right because there are times when you need to prune them, for example, to remove dead flowers and stems as well as pruning established plants that have become leggy.
To sum it up, remove dead flowers throughout summer unless you want to collect seeds, prune out any dead stems at the end of winter and prune any established leggy by a third in spring. Read on to learn more about different techniques and pruning in more detail.
When to prune a tree peony
The answer to when you should prune your tree peony is a little complicated.
With a tree peony, you want to remove flowers that have finished. To do this you want to cut them off directly above the new growth along the stems. This is the process you should do in the summer. If you are planning on collecting seeds you can wait to do this until autumn after you have collected your peony seeds.
Removing dead shoots
At the end of winter, it’s time to remove any dead shoots and cut back your peony to the point of the next healthy bud.
Pruning leggy stems
In the autumn the stems might get a little leggy with time, so use the onset of cooler weather to cut back any long stems by around a third, but do so after the leaves have fallen. This will help you to encourage a bushier shape and this is something that will become more important the older your plant is.
Some tree peony varieties will produce upright, vigorous stems, like the Paeonia delavayi f. lutea and P. delavayi. If you have a peony that is more vigorous, you can remove the oldest stems by cutting them back to ground level in the autumn. This will help to control the size of your plant, which by direct extension, will allow for better flowering come spring. Only remove a couple of long stems every year, this should ideally be done over a few years.
How to prune tree peonies
Tree peonies will respond well to pruning, especially if you do it at the end of winter or the beginning of spring, right when you see the buds starting to swell and shoot.
However, if your tree peony is still only fairly young, say 1-2 years old, the only pruning you should be doing is removing dead stems by cutting them back to the next live bud. If you can’t find the next live bud, you can always cut back your dead stem to ground level. Just remember that younger plants shouldn’t be pruned like this because they need time to establish themselves.
With more established, mature tree peonies, you can hard prune the oldest stems to approximately 15cm above ground level if you want to encourage new stems. But, most important is to spread out your hard pruning over a handful of years, pruning back just one or two of your main stems each year. Do not do all of this hard pruning at once. By spanning it out over the course of several years you will help your tree peony to develop the framework of stems that you want without reducing the flowers you receive.
So by paying attention to the age of your tree peony, and figuring out what type of pruning it actually needs, you will know when and how to keep your peony in good shape, both literally and figuratively.