How to practice smart pruning

Many gardeners are entirely too eager to prune shrubs and trees, which is a way of inventing unnecessary work. There are many good reasons to prune and, in fact, some plants can never reach their peak of health and beauty without regular, thoughtful pruning. Consider the following tip for learning to prune, and compare them to the pruning needs you see in your yard.

Any time is a good time to relieve plants of stems or branches that have died or seem to be in the process of doing so.

• An easy way to determine if a branch is dead is to scrape away a small piece of bark. If there is a layer of green tissue just beneath the bark, and the branch is flexible and not brittle, the branch is alive.

This is the real purpose behind pruning young trees, and you can also prune some shrubs to bring out the best in their natural shapes. However, not every young tree needs this type of pruning.

• Necessary pruning is for only those with branches that cross or rub against each other, causing wounds that are entry points for disease; those with very acute (small) crotch angles as they tend to split in storms; trees where you wish to eliminate low-hanging branches; or dense shrubs that need to be opened up to allow light and air to reach the centre in order to discourage fungal infections.

When left to their own devices, many shrubs will grow foliage so dense that flowering suffers. Roses are an excellent example, particularly reblooming roses, such as hybrid teas. Other reblooming shrubs, such as bluebeard and buddleia also flower more and longer when old branches are cut back. Yet this pruning goal is not limited to reblooming plants.

• Thinning out old branches from forsythia, hydrangea, lilac and mahonia greatly improves the vigour and flowering performance of healthier branches that remain.
• Up to a third of the branches can be removed from a shrub each year without affecting its appearance or health.

Old age is relative where plants are concerned.

• Young or old, bluebeard grows best when it is cut back nearly to the ground each spring, and buddleia grows back best from a 30 to 60 centimetre (12 to 25 inch) stump.
• With red-osier dogwood, the best stem colour develops on one- and two-year-old stems, and cutting out old ones is the best way to keep plenty of new ones coming on.
• As for huge old shrubs that need large-scale renewal, the best approach is to thin out old branches gradually, over two to three years.

Do not hesitate to prune off limbs or branches that are riddled with holes that are oozing sap or are surrounded by sawdust, which are made by boring caterpillars.

• Plant tissues that are badly damaged by pests seldom recover completely, so there is little reason to prolong the plant's suffering.
• Trim off and dispose of branches that are disfigured with corky looking galls (tumour-like abnormal growths), or any that appear hopelessly lost to mildew or fungal leaf spot diseases.

Remember to always assess your plant's current situation and proceed carefully. Choose from the techniques described above to do the job right and you're sure to help your plant enjoy a healthy life.