Gardeners who have ornamental trees and shrubs know that sooner or later they will have to prune. However, many are still reluctant to tackle this task. 

They have the awareness to prune but many times do not know how or when to accomplish this without ruining the aesthetics of the plant. Thinking about the reasons for pruning and the basic techniques before starting would make the task a lot easier.

There are several logical reasons to prune. In general, it is to maintain the overall health of the plant and to improve the quality of the flowers, foliage, or fruit. Pruning can also be used to restrict growth. This comes into play when a tree was planted too close to the house. Many times, it is to remove undesirable growth, dead or broken branches and to prevent damage to property or life. However, there are times when it is desirable to carefully prune for curb appeal.

Pruning success is more likely when using good pruning tools. Use a hand shear for branches up to 1½ inches and a lopper for branches over 2 inches.  Avoid the “anvil” shear and use the “bypass” variety for cleaner cuts.

 Branches over 2 inches would require a pruning saw. Since you are not building a house, put the carpenter saw away. A pruning saw and carpenter saw are built differently. One cuts on the “pull” (pruning) and the other one cuts on the “push” (carpenter). Besides, the teeth are different. Notice I did not mention a chainsaw and stepladder as necessary tools. I tried this once without much success. I didn’t know what hurt the most: the stitches in the emergency room or my wife saying, “I told you so.” Trust me on this, a pruning pole is a lot safer.

There are several basic pruning techniques that you should know before starting. Pinching is the process of removing plant growth at the tip of the stem. This is done by hand and is a good way to control plant size.

Plants that are not pinched will be taller and narrower, while plants that are pinched will be shorter but broader. Thinning cuts completely remove branches back to the main branch or trunk. While using this type of cut do not cut into the main trunk.

Always leave a “trunk collar”. Reduction cuts include shortening branches back to a good bud or lateral branch. A proper reduction cut should not leave a stump. Make the cut about ¼  inch above an active bud or lateral branch.

When to prune varies based on the tree or shrub, but there are some general guidelines to follow. Trees and shrubs that bloom early in the spring on last year’s growth (old wood) should be pruned immediately after flowering. This would include lilacs, rhododendrons, forsythia, azaleas, flowering crabapples, flowering plums, and magnolias.

Those that bloom in the summer or fall on new growth (new wood) should be pruned in the winter after the first freeze or in the spring before the ground is warm enough to start growth. This would include Bradford pears, butterfly bush, crape myrtle, flowering dogwood, honeysuckle, wisteria, and hawthorn.

When you need to rejuvenate an old tree or shrub you will need to go against the standard rule of pruning a spring flowing tree or shrub after it blooms and instead prune it during its dormant season. This will cause less stress on the plant, give it more time to heal and decrease the chance of disease. The major drawback to this is that it will lose one year of blooming. However, it will be worth it in the long run.

The secret of good pruning is to have sharp tools, no step ladder, and some self-control. Pruning is a general maintenance task for every gardener so evaluating trees and shrubs for pruning on a yearly basis is a good idea and never remove more than 30% of the plant’s growth at one time. By the way, treating the cuts is not necessary. Just make a clean cut with the proper tool and in the proper location and everything will be fine. 

 Joe Johnson is a Master Gardener with the Sandusky and Ottawa counties extension offices.