Pruning: A Short Primer

March 18, 2008

We are sure you have seen certain trees around your neighborhood that look like someone used a chain saw to prune them. Such trees have been “amputreed” rather than selectively pruned, by a person who perhaps was unaware of how proper pruning techniques not only improve the appearance of a plant, but also promote its health and ease of maintenance.

If you are interested in improving your pruning knowledge and/or skills, a good pruning book with plenty of illustrations and different plant types is your best initial source of information. Additional literature is also available through the county extension service (425-338-2400), and through the Seattle-based organization Plant Amnesty (206-783-9813) which give pruning seminars at the annual Flower and Garden Shows.

Before you undertake pruning, it is important to begin with the proper tools. The tree or shrub you plan to work on will dictate the type and size of the pruning tools required. For basic lighter pruning, you will need a pair of hand pruners that fit your hand size to avoid muscle fatigue, a pruning saw and a pair of loppers. Even if you are just starting out, we strongly recommend investing a little extra money in good quality tools.

If you already have your own tools, be sure they are in good repair before you begin. Sharp cutting tools are safer than dull tools, are less fatiguing to use and will make nice clean cuts. Once those tools are sharp, it is important to remember to wear gloves. A last safety note…if you are working from a ladder, it is always safer to move the ladder than to overreach and risk a fall.

Thinning, false heading, and heading cuts are the three basic pruning cuts. The thinning cut is best for most of your pruning needs. This cut is done by removing the entire branch at its base. Use the outside of the branch collar as your guide for the cut. The branch collar is found at the base of the branch and resembles a wrinkled ring. Try not to cut into the collar because this is where the specialized cells are that scab over the wound.

For large branches you may need make an undercut. This will prevent the weight of the branch from peeling the trunk’s bark if it should fall before the cut is complete. First place a cut one third the thickness of the branch on the underside at least one foot away from the trunk. Next, remove the outer portion of the branch in manageable lengths. Finally, remove the inner section of the branch by using the branch collar as your guide.

A false heading cut is done by cutting the branch above a bud along its length. This is used in pruning roses and “caning” plants to train a particular branch in a certain direction. It is not recommended for larger branches as it will cause that “amputree” look.

Finally, the heading cut is the least desirable for tree and shrub maintenance. It is the cut that leaves those unsightly stubs extending beyond normal budding points. Damaging the tree in such a way will not only cause poor health, but will also cause the tree to go into a shock of sorts, producing water sprouts, commonly called “suckers” and excessive weak growth.

Now that you have the basics on how to prune, where do you start? Using the 4 D’s method will be your best guide. Dead, Diseased, Damaged and Deranged in this order will be your best guide. Removing dead wood will considerably lessen the density of any tree or shrub, and will also allow more light in for better growth. Next, look for any diseased wood and remove it. Branches that have been broken or damaged should also be removed. Take another look at your work. Branches that are badly crossing or misshapen should be removed as well. If your tree or shrub still looks too full, simply thin out some of the branches a little at a time, always checking your work as you go.

February is generally one of the best months to prune deciduous trees and shrubs, so get out there and get busy!

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