I have some shrubs that have grown too large for the area where they are planted. Is this a good time to prune them? How about trees?
Fall is one of the best times of year to prune. It is easier to see where to make pruning cuts on plants that have lost their leaves. There is one group of plants that’s better to wait to prune. Spring flowering shrubs such as rhododendrons, azaleas and lilacs have already set their flower buds for next spring. Pruning them now would remove most of the flowers. Prune them in late spring or early summer after they have bloomed.
Most needle evergreen trees require little pruning other than shortening an occasional extra-long branch. If the top of an evergreen tree becomes damaged and several branches begin to grow upward, all but one should be removed so that it can continue with a single top.
Lower branches of newly planted deciduous trees should be shortened to about 6 inches but not removed entirely. These branches feed the lower trunk so it can grow stronger. Keep them short for three or four years, then remove them entirely.
In addition to removing dead branches in deciduous trees, other branches that are rubbing and crossing each other can be thinned. In most cases, branches should be cut back to their origin, rather than just shortening. In choosing which branches to remove, leave the ones growing outward, and remove those that grow inward or straight up. When removing branches larger than 2 inches in diameter, leave a half-inch collar. This collar contains healing tissue to close the wound.
Reducing size is often one of the main goals of pruning shrubs. However, pruning every branch that grows beyond the desired outline of a reduced size will stimulate an explosion of growth next spring. Several times as many branches will grow, producing a plant that is much thicker.
To keep the natural thickness of shrubs, prune one branch at a time. If possible, branches should be shortened back to a side branch. If no side branches are growing on a particular branch, prune just beyond a bud or remove the branch entirely. Don’t prune every branch to the same length. The natural shape of shrubs is not perfectly round or flat on the sides or top.
If growth is too thick, remove entire branches back to their origin. Shrubs should have a tapered shape with lower branches slightly longer than those growing above. If upper branches shade lower ones, the lower branches will gradually lose their leaves creating a bare look.
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