How to Prune a Garden Plant

There’s a strange aura that surrounds pruning that seems to make people act in one of two ways.

They either rush in full force and hack the offending plant back until, usually about half way through, they realise this might not have been the best idea, or they have the opinion that plants have always been able to look after themselves in the wild so why should a garden plant need to be pruned?

The reason why garden plants need to be pruned is that most have been bred to have oversized flowers, more fruit or longer, straighter stems than their wild cousins.
 

Because of this special breeding our garden plants are now dependent on us humans to prune them to keep them at their best.

Almost all plants are going to need some type of pruning at some point in their lives even if it is just to remove dead, diseased and dying tissue (often referred to as the three D's).

It's when a garden plant needs more than a quick prune to tidy it up that people tend to worry. One of the hardest questions for the beginner is deciding what type of pruning is required and when?

There are far more types of plants than I could ever mention in this article so here we're just going to cover the basics to start off with.

The very first step to successfully pruning any garden plant is to resist those secateurs and just take a moment to have a close up look at your plant and answer these questions:

If your garden plant is still young and soft with stems thinner than your little finger, a pair of secateurs will probably do the job. If, however, the branches are thicker or the wood is particularly hard then loppers would be better suited.
 

If you are unfamiliar with loppers these are simply a larger more powerful pair of secateurs on extended handles. They allow for greater leverage when tackling plants with larger branches.

How Thick are the Branches you need to Prune?

If you are still unsure whether you should be using loppers or not it is always a good idea to try cutting a branch off and seeing what happens.

If the secateurs get stuck and you find yourself tempted to twist them to force the blade through then STOP. Don't go any further. You will regret it if you twist the blades. You may well manage to get that branch off but in the process you will have ruined your secateurs.
 

Twisting the blades will eventually result in them not meeting and instead of cutting the stem they will simply snap it. So if they should get stuck in a branch that is too thick, carefully remove them from the wood and reach for the loppers.

Any tool used must be clean and sharp. A cut, even a pruning one, is a wound on the plant and a ragged crushed stem is far more susceptible to infection than a clean neat one.

Cuts should be kept to a minimum and should be as small as possible.

Again, the larger the cut the higher the chance of an infection entering the plant. There is much debate on whether a cut should be slanted to allow the rain to run off, or straight to keep the wound small. Personally I prefer the straight cut, but whichever method you decide to use there are some ground rules.

Always prune as close to a bud as possible without damaging it. Any material left above the bud will eventually die off and leave what's often called a 'snag'.

This is a piece of dead wood between two shoots that is not only an excellent place for diseases and pests to hide, but is also one of the main calling cards of bad pruning!

Cutting close to the bud also means that the cuts will be well hidden. Ideally, once you have finished, the plant should still look as natural as possible, almost as if it had pruned itself.

Slanted cuts work much better where you are pruning to just one bud rather than two buds opposite each other on the stem.
 

The key to success with slanted cuts is to make sure the slant is in the right direction and is in the right place.

The cut should slope gently away form the bud and end just above the bud (see right).

This is not always as easy as it sounds. If the buds are very small or very close together, or if you are pruning a plant with opposite buds such as an Acer or Cornus then the straight cut method may be easier.
 

The main problem when pruning using both kinds of cuts is dying back. This happens when the cut has been made at too sharp an angle and only a thin slither of stem, with a bud perched on the end of it, has been left. As there is not enough transpiration taking place to draw the sap up the stem it will die back to the buds below in the same way as a 'snag' (see below).

New stems grow from the lateral nodes (buds). These are the ones that can be seen growing from where the leaf joins on to the stem. Once the main stem has been cut the plant will direct its growth energy to these smaller buds and they will begin to grow more vigorously. Pruning like this will result in a smaller bushier plant.
 

When Does Your Garden Plant Flower?
 

Before you start your pruning you will need to decide if you are doing so at the right time of year.

For example, if you were pruning a mop-head hydrangea and decided to cut it down to the ground in spring then you would have removed all of its flower buds for this year and it could be a couple of seasons before it flowers again.

Some plants, such as the mop-head hydrangea, flower on old wood from last season while others flower on new wood grown this season.

The hydrangea should be dead-headed after flowering or in spring, then if the height needs to be reduced some of the branches could be cut back to a lower bud.

This way you get a smaller plant but you still get some flowers.

Summer Flowering Plants

If your plant flowers in the summer, on new growth, then prune it in spring when there is no longer any chance of a severe frost.

Cut it back to just smaller than the required size. This will allow the plant to grow to its desired size and then flower.

Always Research Your Plant before Pruning

There is an almost infinite range of pruning methods and plants that need some type of specific care. Some of these issues will be covered in other articles, but for now all I can say is a little research into your garden plant before you cut it back will go a long way towards better pruning, and you'll have a healthier plant in the garden as your reward.

© Lauren Berry 2007.
This article must not be reproduced without written permission.