Mild January Days Ideal for Pruning

Almost all woody plants will benefit from pruning at some time or another. Some kinds should be pruned fairly severely each year to keep them within bounds or to renew flowering wood. Others need only very little pruning to remove weak or dead wood, or to direct the growth for good shape or form. For example, it’s best to prune camellias and other early spring flowering plants after they bloom, hardy deciduous fruit trees before they bloom and borderline hardy shrubs after the weather warms.

When to Prune ---- Some say it is possible to prune “anytime the saw is sharp.” This expression is not totally correct; some seasons are better for pruning than others. For most trees, late winter or early spring is the ideal time for pruning. Wounds made by removing branches at this time will begin to develop callus tissue with the approaching growing season. Insect and disease activity is at a low level. Since the tree is dormant, no foliage is removed and the food producing capacity of the tree is not affected. Finally, absence of foliage makes it easier to get an overall view of the general structure of the tree.

Some trees such as maples, walnuts and birches bleed profusely when pruned in the spring. They can be pruned in the late fall or in the winter before there is any sign of spring growth. They can also be pruned lightly in the summer.

Early blooming shrubs should not be pruned now—wait until after the blossoms have faded. Pruning will consist mostly of cutting out the older, branched or twiggy growth. These shrubs will grow new wood and form fruit or flower buds before the end of the growing season.

How to prune-----For most gardeners, deciding where to cut is the hardest part of pruning. These suggestions may help. First, cut out dead, diseased and weak, twiggy growth. Next, cut out or shorten branches, shoots or twigs that are going in the wrong direction, getting out of bounds, or crowding and crossing over others. To finish the job, thin out, where necessary, for even spacing, ease of spraying, and to maintain moderate growth. Moderate growth each year means good annual flower production. When making pruning cuts, cut back to a side shoot, branch, or bud.

Some shrubs, like lilacs, rhododendrons and azaleas, produce new growth at the tips of canes and branches each year. For the most part, these shrubs need only to have weak growth thinned out. Occasionally they may be cut back to keep them in bounds.

Other shrubs like spiraea, forsythia and beautybush send up new un-branched canes each year. These canes branch the second year but do not grow from the tip. Some new canes should be left each year. Canes that are three years old or older should be removed.

We are confused! Aren’t you supposed to always cut flush with the trunk or limb when pruning off branches?

For many years, horticulturists and arborists recommended making pruning cuts flush with the trunk. Now, the recommended practice is to make the cut just outside the branch bark ridge at the base of the branch without injuring the ridge or the branch collar.

The branch bark ridge is the wrinkled bark line that forms where branches join the trunk. On conifers, it encircles the branch (collar-like) while on hardwoods, it drapes over and down the sides of the branch junction like a droopy mustache. Cutting between the main trunk and the ridge or into the ridge itself, partially destroys the ability of the wound to seal over rapidly and decay will result.

Remember to consider branch size when pruning. Pruning large branches takes years for the wound to seal. To promote lifelong tree health and safety, plan regular and early pruning when trees are young and branch diameter is small. This reduces the cut surface area and potential for decay.

Trees that have broken limbs, not infected with decay, can usually be repaired with proper pruning. Generally, if the branch has not split away from the trunk, the broken segment should be removed back to the next major branch. Do not leave branch stubs since they encourage rot and decay.

To avoid stripping the healthy bark from the trunk when a heavy, broken limb is removed, the 3-step procedure should be used. The first cut is made on the underneath side of the branch about 18 inches out from the trunk. The cut should be approximately halfway through the branch or until its weight first starts to bind the saw. The next cut should be made on top of the branch about 1 to 2 inches in front (toward the end of the branch) of the bottom cut. Continue cutting until the branch drops free. The last cut removes the remaining branch stub from the trunk. The cut should be made from the top of the branch at the branch collar. The branch collar is the slight ridge where the branch attaches to the tree’s trunk or another major branch.

Every time our neighbor makes a pruning cut, he paints on that black tar substance over the freshly cut surface. He says this protects the newly cut surface. Our other neighbor told us we should not do this. Who is right?

For decades, garden experts recommended that a substance should be applied to fresh pruning cuts to prevent disease organisms from becoming established. Horticulturists are now recommending just the opposite. Research has shown that the application of tree wound dressings actually delays and in some cases prevents the natural healing of the cut surface by sealing in moisture and decay. This prevents wound wood from forming and inhibits compartmentalization. Wound dressings do not prevent the entrance of decay organisms and do not stop rot. In fact the dressings almost always eventually crack, exposing the tree to pathogens.

Editor’s Note: This article first appeared on www.hometowndebate.com 1/11/13. If you would like to respond to this story go to hometowndebate.com