Horticulture Magazine

How (And When) To Prune And Cut Back Pieris

pieris japonica leaves

Pieris are useful evergreen shrubs for your garden, but understanding their care includes learning how and when to prune.

One of the reasons that Pieris is such a popular garden plant is that it is a great low maintenance option for your garden.

Pieris Japonica and Forest Flame are two incredibly popular shrubs in the UK and neither requires too much effort from gardeners.

One job that you might like to think about each year, however, is pruning your plant.

Pieris shrubs may not necessarily have to be pruned at all. If you are happy for them to grow more naturally and grow to their full potential, you can more or less leave them to their own devices if you prefer.

If you are a proponent of natural gardening then this may be the approach you decide to take.

Pieris is usually only ever pruned lightly, and this is often more for the sake of appearances than for the health of the plant.

Leaving your Pieris largely unpruned can often be the best choice for wildlife, and if you do decide to prune your Pieris, less is usually more.

However, pruning Pieris shrubs correctly can sometimes be beneficial. It can allow you to maintain their shape and size, and deadheading after flowering might not be strictly necessary, but it will often be a good decision for the appearance of your garden and may make new foliage even more impressive and spectacular.

Why Prune Pieris?

red and green pieris japonica

You might prune Pieris:

  • Simply to remove dead, damaged or diseased material if there is any.
  • Because it has grown large and has outgrown its location.
  • To improve its shape and form if it has become lopsided or unappealing aesthetically.
  • To gently restrict its growth and keep it in check.
  • To remove dead flowers to keep your garden looking neat.

How to Prune Pieris

Pieris falls into RHS pruning group 8, which includes early flowering evergreens.

Simple Maintenance Pruning

Most of the time, Pieris will only require pruning to remove any dead, damaged or diseased material.

Take a good look at your shrub and aim to take out anything which seems to have any problems with a clean, sharp pair of secateurs, loppers or another pruning tool.

Often, this will be enough.

Hard Pruning

If your Pieris is very large and overgrown, you can undertake hard pruning to rejuvenate it entirely, by cutting out around 1/3 of the old wood and, if necessary, cutting back hard to the required size and shape.

Hard pruning will likely lead to loss of flowering the following year, and perhaps the year after that.

However, the flushes of new colour and the size restriction can mean that this is still a good bargain. And Pieris, though they do not regularly require it, do tend to respond pretty well to hard pruning if they are otherwise healthy and in the right location.

Another thing that you might consider with a mature and large Pieris is pruning it into a standard form (making it look more like a tree than a shrub).

With some types of Pieris, you may be able to remove lower stems around the main trunk, starting at the ground and working upwards, to turn it from a shapeless shrub into a more attractive garden feature.

So this is something else to consider for a mature and currently unappealing Pieris shrub.

Deadheading

white flowering Japanese Pieris

You may also wish (largely for aesthetic reasons) to deadhead your Pieris, even if you do not need to do any other pruning.

Removing flowers as soon as they have faded can help keep flowers coming. And when the plant has finished its blooming period and the later flowers are beginning to go to seed it can keep your shrub looking neater and more appealing.

Simply snip off each of the spent flowering stems to a healthy bud. Do not confuse the flowers for the colourful bracts of young leaves.

One thing to note however is that deadheading is not really necessary – if you leave the flowers in place, they will usually fall off of their own accord. And deadheading and being too neat and tidy in your garden is not always, in general, the best thing to do for wildlife in your garden.

However, deadheading may also help plants focus on creating beautiful new foliage growth. It is also worth noting that Pieris are usually grown mostly for their attractive foliage rather than for their flowers.

Maintaining Shape and Size

At the same time as deadheading after the flowering period, you can also trim branches lightly here and there to maintain a desired shape and size.

Just make sure that you do not cut into too much of the new growth which will produce next year’s blooms unless you have decided on hard pruning.

When To Prune Pieris

Since Pieris are in pruning group 8, they should always be pruned immediately after flowering, in spring.

Most Pieris will bloom between March and May. So May or early June is a good time to prune in the UK – and also a good time to take any cuttings for plant propagation.

Like other shrubs in this group, they require little pruning and as mentioned above, you may not need to do much pruning at all.

Certainly, it is important to avoid pruning Pieris after the end of the summer, since this can spur new tender growth which can be damaged by frost and cold temperatures in winter.

Post-Pruning Care

a large pieris shrub that has been heavily mulched
Pieris with mulch

Pruning correctly does not end with cutting off the plant material. After pruning your Pieris, you should also take care of it by adding a good quality organic mulch.

Replenishing a layer of leaf mould, compost or well-rotted manure, or other organic material each spring will make sure there are plenty of nutrients for the shrub to uptake throughout the rest of the growing season.

You should also think about feeding your Pieris (especially if growing in a pot or container) with a good general-purpose organic liquid fertiliser (a homemade compost tea, for example).

This will give plants a boost after pruning and help make sure they respond well to the pruning with healthy new growth.

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