PRUNING: TIMING AND TECHNIQUE

Pruning is vital to the health and beauty of trees. Pruning controls the size and direction of growth, improves a tree’s health, diminishes risk of infection and increases the size of flower and fruit production. Proper pruning also encourages growth by opening up the tree’s canopy and branch structure.

But first and foremost, proper pruning is important for tree health. Dead wood that is left on a tree is a food source for fungi and bacteria that can damage a tree. Such dead and decaying wood can also open passageways for invasive insects.

TIMING

On most trees, the ideal time to prune is during the winter months when sap flow has either stopped entirely in northern regions or slowed considerably in southern regions. Early spring is also a good time to prune, as long as trees have six weeks of healing time before the first signs of growth.

There are exceptions. Trees and shrubs that flower in the early spring, such as lilacs and redbuds, are best pruned within the two-week period following blossom drop. Many varieties of needled evergreens are best pruned in the spring as well, just as new growth emerges.

Pruning should be matched to the needs of each tree, in technique and timing. Some trees require frequent pruning while others require very little.

PRUNINGTECHNIQUES

Before pruning any tree, determine the objective. There are several reasons to prune a tree. As a general rule, prune a tree first for safety reasons, then for health, and then for aesthetics.

No matter what the reason is for pruning, as a general rule of thumb, remove no more than a quarter of the tree’s foliage.

Pruning techniques vary depending on the size and location of the branch.

When a small branch is pruned away, the cut should be made close to where it emerges from a larger branch. This way, the plant’s natural growth pattern is encouraged. Cuts on branches or stems should be made at a moderate angle; too great an angle exposes a large, oblong wound that takes longer to heal and is more susceptible to infection.

When trimming side branches, the final pruning cuts should be made at the outside edge of the branch collar (the slightly swollen area where the branch attaches to the trunk). On larger, heavy branches pruning cuts may have to be made several inches from where the branch emerges, to avoid any tearing of the bark when the branch falls.

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