Late Winter Pruning

Late winter and early spring is the time to prune many shrubs and small trees in the yard. Shrubs that bloom in summer and fall generally develop flowers on current seasons growth and should be pruned before the first flush of growth in the spring. Shrubs that bloom in the spring or winter should be pruned immediately after flowering has finished. Pruning is practiced to maintain plant health, control plant growth, and encourage flowering and fruiting. These objectives should be remembered as you prune.

Pruning should encourage plant health, not plant disease; therefore, it is important to prune properly using the correct pruning tools. For general cleanup hand pruning shears are used, loppers may be used for branches up to one half inch, a pruning saw can be used for larger branches and hedge shears should be used to trim closely clipped hedges only. All tools should be kept sharp. Sharp tools not only cut easier but will not bruise the plant tissue. Bruising the plant causes slower healing of the wound and causes an increase in the probability of disease.

A clean cut should be made. This means the cut surface should have a smooth surface not a rough one that looks as if the tissue has been torn or pulled. Care should be taken not to injure the plant around the cut, or rip or tear the bark above or below the cut. The cambium layer, a thin layer of cells just below the bark which is important in wound healing, is easily injured. Do not twist or turn the shears as you cut because you will injure the plant as well as your shears.

Painting the wounds with tree wound dressing has lately become a controversial practice. The standard recommendation has been to paint all wounds over 1 inch in diameter with a quality tree wound dressing to protect the cut surface from woodrotting organisms and checking (radial cracking) upon drying. Some research has shown that upon exposure to the sun, the protective coating often cracks, and moisture enters the cracks and accumulates in pockets that may occur between the wood and the wound covering. This situation would be even more inviting to wood-rotting organisms than one with no wound cover. However, in situations where aesthetics are important, the practice is justified. If a pruning wound is to be protected, allow it to dry before applying the dressing. This will improve chances of good bonding. Examine the coating several times the first year. Retreat if the coating has cracked.

Clipped hedges require a specialized type of pruning and may become a continuous job during the growing season. There are two important factors to remember about clipped hedges. The hedge should be clipped while the new growth is green and succulent. Also, the plant should be trimmed so that the base of the hedge is wider than the top so that light can reach the lower leaves.

Unless a shrub is a topiary, espalier, or part of a formal hedge it should not be closely clipped but allowed to develop into a naturalistic form. This does not mean that the plant should be left alone, but that pruning is done to enhance the natural beauty of the plant. The first step in pruning is to remove all dead, diseased, or injured branches. Once this is done it may be necessary to thin out the plant. Remove branches that cross each other or they will obviously become entangled. If the shrub still looks too thick remove some of the older branches. Remove any branches that are distinctly different from the rest of the shrub. Cut back excessively long growth to a bud that is four to six inches below the average branch length. If you wish to reduce the size of the shrub cut back each branch four to six inches, to a new bud. Do not use hedge shears but cut each branch separately. This will provide a neat, informal shrub that retains its naturalistic shape.