Pruning, principles of pruning garden plants

I get more enquiries about how to prune plants than any other subject, so this page is an attempt to explain the principles of pruning.

I will cover how to prune the mature plants that you may already have in your garden as a part of regular maintenance. More detailed pruning such as how to develop the shape of a tree over time for instance so that it is balanced and pleasing to the eye, or a convenient size and shape to pick fruit from is beyond the scope of this article.

Principles

The rule of thirds. When pruning either reduce the number of stems of shrubs down to ground level by a third (take out the thickest each time) or reduce the stems by a third of their length.

Little and often. Like all living things, plants respond best to little and often. Pruning of shrubs should be done on an annual basis, severe pruning for the rejuvenation of a large neglected plant is sometimes necessary, but should be seen as an emergency measure, rather than a standard procedure.

Prune after flowering. As a rule of thumb, if in doubt prune immediately after flowering. This is not a universal rule, but applies to the majority of plants. It prevents the plant from putting energy into seed formation and ensures that you enjoy the maximum number of flowers for that season. Likewise remove dead flower heads if the plant is likely to keep flowering.

Always remove dead stems and branches as soon as you notice them - Irrespective of time of year. Dead wood will attract disease which may well spread to the healthy parts of the plant.

When removing dead wood, cut back into live material. For the same reason as above.

Always use sharp secateurs or loppers. If your cutters are blunt, the branch or twig may crush or tear, this results in a jagged edge that makes it much easier for disease to take a hold.

Pruning a mature plant will stimulate growth. This can be a way of rejuvenating a large neglected plant. You also need to aware that this stimulation will happen whether you want it to or not! If you are pruning because a plant has grown too large, its first response will probably be to keep on growing, so you may need to remove the new growth too after a little while.

If there are no buds in the area of the cut, then (as a rule of thumb) the plant will not grow back from the cut. With a few exceptions, plants will not grow new green shoots from dormant brown wood.

Remove suckers as they appear. Suckers are very strong, fast developing shoots which grow straight up from roots or branches. Their stems are usually bigger but not as strong as ordinary branches. If suckers have different foliage, they are growing from below the graft. Follow them back to the main stem and remove them carefully.

Pruning cuts should always be made into live wood or stem. They should be made just above a growing bud and slope downwards away from the top of the bud. The bud cut above should be facing outwards from the centre of the plant so that when it grows, the new growth will grow into a space, rather than inwards and compete with existing shoots

If annual pruning is neglected, naturally prolific shrubs soon accumulate masses of old dead wood in the centre. This can result in excessive size and diminished flowering. Rejuvenate them during their dormant season by first cutting out surplus material such as dead, diseased and crossing stems, and thinning the number of remaining stems by up to a half.

The bush is more likely to survive drastic pruning if the process is spread out over two seasons.

Shrubs that respond to severe pruning, such as Ribes and Philadelphus, may be cut almost to ground level to re-establish a framework of new shoots. But, if the shrub is elderly and revival is uncertain, take cuttings as an insurance. Cut out any dead, diseased or decaying wood from the shrub and remove crossing branches. Remove half of all the healthy shoots to leave the others room to develop.


Secateurs Sort of "super scissors" for the garden. An absolute must for all pruning jobs. These are Felco No.2, reckoned to be the best you can get. For materail to about little finger thickness.	Loppers For larger branches. This pair will cope with material up to 25mm (1") in diameter. Loppers are easier and generally safer for many heavier pruning jobs than saws.	Pruning saw. This is used for thicker material, above 25mm (1") in diameter. Saws should also be used for cutting all dead material, they are easier to use than loppers for such jobs and give a cleaner cut.

Mature trees in general don't like being pruned. If you're thinking of planting a tree, then go for one that you will be happy with once it has reached its final mature size.

There's nothing quite as sad as a tree that was planted in the wrong place and then later in its maturity had to have some major surgery on large branches that results in a stunted stumpy look.

If you do have to perform major surgery on a tree, first of all find out if you are in a conservation area or if the tree is protected, then consider calling in the professionals. If you're not sure what you're doing, it can be dangerous to you, harmful to the tree and result in a mutilated tree that will possibly never recover during its life-time (or yours).

Most tree pruning should be limited to the removal of dead branches or those that have been torn off by the wind. In both cases cut back to the nearest major junction with another branch. If you look carefully, at every major junction of branches is a raised ridge. This is the natural place where the tree will cut off all contact with the branch if it becomes damaged. Don't cut into or behind this ridge, the tree can then better cope if any disease infects the dead region.

The dormant winter months are an ideal time to prune the over congested spurs from pome fruits. Apples and pears are mainly spur-fruiting trees, meaning that the fruits are produced on short lateral branches some 6-12 inches long. When a tree has been growing for some time, these spurs become over-crowded. The result is a rather untidy looking tree, lots of blossom and lots of small and not very high quality fruit. If you reduce the spurs, then the overall yield won't increase, but you will get a good improvement in the size and quality of the fruit that form.

Remove the older more complicated growth and thin weak stems leaving young vigorous growth behind. It depends on the state of the tree, but you should be aiming to remove about a third of the spur stems. If you repeat this process every year or tow, then the tree will eventually be fruiting only on wood that is no more than a few years old.

The dormant season is the best time to this for apples and pears, when the buds begin to burst it's too late.

A drupe is a fruit with a stone, plums, cherries, peaches and apricots. Drupes on the other hand are pruned in the summer when in growth as winter pruning for these carries a high risk of introducing disease. This also applies to Ornamental Prunus species such as ornamental cherries and almonds.

There are commercially available paints of various types that are sold to paint on the cut ends of large pruned tree branches. Research has shown that these fulfill no useful purpose and in some cases have been shown to actually seal in disease causing organisms and make the stump more likely to rot.

More importantly, ensure that the cut is as clean as possible so that there is the minimum area for fungus etc. to enter. If the cut is clean, then it will seal naturally all the quicker.