Ask An Arborist: November 24, 2009
Proper Crape Myrtle Pruning
Suzanne from Hoschton Writes...
"I've heard that you're supposed to prune most trees in the winter but I'm not sure if that is correct. Also, how much can I prune back my trees and when should
I do it?”
I posed this question to Art Morris, Board Certified Master Arborist with Bartlett Tree Experts.
His Answer Is...
For many trees, pruning can be done any time of the year, however winter is a great time to take care of most pruning needs.
Depending on the type and extent of pruning your trees require, an arborist may recommend pruning during either the growing season
(spring/summer) or dormant season (fall/winter).
For example, crown cleaning (the removal of dead and broken branches) can be done any time of the year because it does not remove
live limbs from the tree. It’s sometimes easiest to perform crown cleaning during the growing season because a trees leaves make
dead limbs a little easier to identify.
Thinning of a tree is intended to reduce the risk of broken branches by reducing weight and wind loading of limbs. Many arborists
recommend minor thinning during the growing season, as long as less than 10-15% of the tree canopy will be pruned. If more
extensive thinning is required, a tree can be thinned by up to 25%; but for pruning this extensive it’s usually best to prune
during the dormant season.
In some areas of the country, where oak wilt and other diseases are common, pruning on selected species of trees is reserved
only for winter. Fortunately, no such diseases are prevalent in Georgia. Because each tree is different, its location and health can influence its pruning needs. An arborist can help evaluate the condition and pruning needs of your tree.
A few other notes to consider:
Below are some before and after examples of proper pruning provided by Bartlett Tree Experts:
- Dormant season pruning on spring-flowering trees may reduce their flowering. This is because they develop flower buds very early, and pruning them in winter removes many of the buds.
- Some species, such as maple, river birch and beech may “bleed” or weep water from pruning cuts. This is especially true when they are pruned in the late winter or early spring. The weeping is generally not a cause for concern, but to avoid it, prune during late summer or fall.
- Ambrosia beetle is a significant insect pest that can attack and kill mature hardwoods. Mature hardwoods that are under stress shouldn’t be pruned heavily during the summer.
- Pruning cuts should not be sealed. Pruning sealant or wound paint can actually cause more disease and decay at the site of a pruning cut.-Finally, homeowners can perform light pruning tasks, but should call an arborist for pruning that requires climbing.
Oak Before Thinning
Oak After Thinning
You can see that the overall shape of this oak hasn't changed but smaller branches that were less stable and probably crossing
have been removed. By summer when the leaves are present, it would be hard to tell that it had been pruned.
Tree Before Crown Raising
Tree After Crown Raising
It's often necessary to remove lower limbs in order to have clearance or visibility underneath the tree. You can see that this
tree was "limbed up" during the growing season because less than 25% of the overall foliage was being removed. If the removal
of the lower limbs was going to remove between 25-50% of the foliage, it would be preferable to do this in the winter. If it was
necessary to remove 50% or more of the foliage, you may want to consider removing the entire tree and planting something else.
My thanks go to Art Morris of
Bartlett Tree Experts for answering this question.
If you are concerned about the trees in your landscape, you can contact a Certified Arborist or a professional tree company in
your area through the web site of the
Georgia Arborist Association.
If you have comments or questions about this article or want to submit a question that may be used in a future article, please
Unless otherwise noted, Images & Drawings Copyrighted © 2009 by Theresa Schrum - All rights reserved