Terran's Tips

Proper Crape Myrtle Pruning

In Memphis there are two landscape staples that we are all very familiar with….Azaleas and Crape Myrtles. Azaleas provide beautiful color in the spring along with the Dogwoods and the Crape Myrtles provide beauty as they bloom in the hot summer months. Proper pruning of these trees is a subject that I have been very anxious to write a tree tip about. I wanted to wait until July because this is the time of year that most Crape Myrtles are in bloom. I would have to assume that the practice of topping Crape Myrtles is more of a product of improper landscape placement and has bleed over into common practice. Not to mention that a Crape Myrtle will tolerate topping. Let’s be very clear and recognize that a Crape Myrtle is a tree and not a shrub or hedge. They may very easily reach heights of 40 feet if let to grow uninterrupted as Mother Nature has intended. When a Crape Myrtle is planted 3 feet away from the corner of a house we are obviously going to have some problems in the future.

When topping any tree there are some post traumatic responses that occur that start a snowball of issues that will cause much more maintenance that if tree were properly pruned in the first place. Many of us in the tree industry have affectionately termed the practice of topping these colorful trees “Crape Murder”. To back track for a moment I would like to mention that in TREE 101 we are taught that the leaf is without a doubt the most important part of any tree or plant. It is the place where all photosynthesis starts; the leaf manufactures sugar energy to stimulate healthy growth. The leaf is a vital part of the transpirational pull which allows the wicking of water and nutrients from the root system throughout the woody tissues and into the leaves to help the tree cool itself. Not to mention the leaf is the location where harmful CO2 gases are traded for the air that we breathe. Once these topping cuts are made, the stubs that are left over produce succulent growth at a rapid rate to compensate for the loss of foliage. These “suckers” grow at a very rapid rate and have a much weaker attachment that the original stem that was cut. This growth is much more likely to break during a windy and rainy day especially with the weight of blooms. To summarize the acute effect of topping a tree may reduce height; however the long term effect is a more problematic situation. One step forward and two steps back if you will. In the picture to the right we can see how busy the succulent growth is. In my opinion this tree doesn’t add to the beauty of the landscaping at this home and has been over pruned.

Proper pruning techniques
In a perfect forest situation a tree grows and we have to do very little maintenance or pruning. The urban environment causes us to prune to clear structures and eliminate dead wood to reduce hazards to personal property. When it comes to Crape Myrtle pruning I suggest that the dead wood in the center of the crown is regularly removed. Any shoots that are rubbing against structures should be pruned back to the branch collar or parent trunk. It is very important not to stub any limbs, this will cause a growth response similar to topping. Also any branches that grow and lean to far away from the central trunk be pruned back to tighten the bouquet, this should reduce the chances of limb breakage.

Please refer to picture to the left. These are two 18 year old Natchez Crape Myrtles at a clients home. Over the years he has done a great job in allowing these two trees to have a regular growth pattern with minimal pruning. He has regularly cleaned the center part of the tree by removing any dead wood and laterally pruned any stems that have grown too close to the house. We certainly don't want any limbs rubbing on any part of the house as this will cause abrasion issues for both the house and the tree.

The picture you see to the right happens to be a Crape that was planted too close to the corner of a house. It is my home and I inherited this problem. Instead of topping or removing the tree I have laterally pruned away from the house, if you look closely you can see succulent growth at the cut points. This is something that will cause an increase in maintenance pruning. Although this tree has unilateral growth away from the house it provides beauty and full blooms while maintaining a transparent feel. If this tree were topped over the years it would be a huge bundle of suckers that would block the corner of my home.

The Crape Myrtles to the left have been properly pruned and have grown in a normal fashion and provide both shade and color in the hot summer months. If you need some help with pruning and maintaining your trees please let us know. We are happy to provide a free consultation with an ISA Certified Arborist.

Please email joanna@woodlandtree.com for any of your tree servicing needs.

Posted by Mark Allen at 14:25
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