Trees and shrubs are pruned to control their size; to improve their vigor and appearance; to give them a desired shape; and to remove dead, injured or diseased plant parts. It is usually best to prune non-evergreen trees in early spring after the danger of severe cold has passed and before they are in full leaf. At this time wounds will heal rapidly with less chance of infection. Pruning of certain trees such as elm, birch and maple, including boxelder, should be delayed until the trees are in full leaf. These trees will bleed profusely if pruned earlier in the spring.

Small branches (less than 1 inch in diameter) can be removed flush with the main branch or trunk with one saw cut or pruning shears. Removing larger branches should be done using three cuts. The first cut should be made one foot from the trunk. Cut about 1/4 the way through the branch from the underside. The second cut is made on the upper side of the branch one or two inches further out on the branch. This cut should be completely through the branch. The third cut is made at the collar adjacent to the trunk, cutting off the remaining stub.

Non-evergreen shrubs, for the purpose of pruning, are divided into two groups based on their time of flowering.

The first group is comprised of early flowering shrubs that bloom from buds produced the previous year. Large white flowering spireas, lilacs, honeysuckles and mockoranges are in this group. These should be pruned immediately after flowering. When pruning, remove the remaining flower and seed clusters as well as cutting out the very old stems and cutting back the larger stems. Avoid removing more than 1/3 of the total stems and branches. If the shrub is very old and leggy, it can be rejuvenated by cutting all the stems back to near ground level in early spring.

The second group is comprised of shrubs that bloom from buds and shoots grown this year. Potentilla, hydrangea, alpine currant and ninebark are examples of this group. These should be pruned in early spring. Rejuvenation would be done as for the group listed above.

For pruning purposes, evergreens fall into three groups, based on the time the pruning should be done and the method of doing the pruning.

Junipers, cedars and arborvitae trees and shrubs may be pruned at any time of the year, preferably from April to mid-August. Do not cut beyond the living (green) foliage portion of the branches.  It's best to confine your work to the younger wood. Use hedge shears on compact "definitely formed" trees and hand shears or a knife on other forms such as low growing, globe or prostrate types.

Pines, except where damaged or diseased wood must be taken out, are pruned in late spring when the buds have elongated and the new needles are just beginning to grow in length.  The "candles", new growth can be pinched back to any length, as long as some of the candle is left. This can be done with a pruner or simply by breaking off the bud end with your fingers. Leave at least one inch of new growth. This pruning will keep low growing pines such as the Mugo Pine in good form and control the size. Large pines can be kept much more dense by pinching back the new growth, especially when the tree is young.

Spruce, a large growing tree, is often planted in a confined space. To keep it in bounds, pruning every year or two is necessary. The preferred method of pruning consists of cutting back on 1 year old shoots (last years growth) making the cut to one of the lateral side buds.  If older wood is to be removed, cut back to another shoot or branch. This should be done just before new growth begins in the spring. Spruce can also be pruned at the same time as pine, by cutting or braking off part of the succulent new growth.

Hedges are pruned to obtain a uniform, compact, pleasing appearance or to keep them in bounds. Hedge pruning should start a few years after they are planted. This causes the hedge to be full and tight from the bottom up by the time it is mature. An important point to remember when pruning your hedge, the top should be narrower than the bottom. This allows the sun to reach all areas of the hedge.

This page was last updated April 2003

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