Patricia M. Arledge, Sharpe, Kenneth W. | 8/24/2011 7:44:58 PM
News Article for August 1, 2011:
I was over visiting with a friend recently and he had some beautiful Natchez Crape Myrtles over hanging his deck. Since it has begun to rain, the bark had just started shedding to expose that cinnamon colored under bark. That is quite an interesting contrast.
This process of shedding the bark is known as exfoliating. It is a natural process in which the bark peels off of the tree in thin flakes, scales or layers and will expose a new bark layer. This characteristic of exfoliating bark occurs in some thin bark trees. As these trees grow and expand their trunk diameter, the outer layer of bark is split and replaced by new bark underneath.
Some of the most popular trees that come to mind that have exfoliating bark are crape myrtles, drake elm, sycamore and river birch. You will also see this characteristic on bald cypress, Chinese elms and eastern red cedar.
You should never help the peeling process by pulling loose bark. Let the tree naturally shed the bark.
The exfoliating feature is foreign to many people and I get a lot of calls from concerned gardeners who think this is a problem. It is not. These trees are genetically designed for this process.
Bark exfoliation is an interesting feature that many people like. The process will start sometime after the trees start to grow in the spring then will be prominent many times through winter, giving interesting detail to the trees. Dr. Owings, Ornamental Specialist with the LSU AgCenter, tells me that the bark shedding tends to be more predominant every other year with a lot of trees. He says that you usually start to see the exfoliation in drake elms after four to five years when they start to significantly expand their trunk size.
An added feature of exfoliating bark is that sometimes the inner bark is a different color than the outer layer. Two of the most striking examples of trees with contrasting bark colors are the Natchez Crape Myrtle with its cinnamon colored bark and the drake elm with orange bark.
Some would indicate that the exfoliating bark is interesting to see but eye appeal is not the main reason that it exists. The shedding of bark is a survival tool used by some trees to shed unwanted pests like scales and other insects. The trees also have the ability to rid themselves of other hitch hikers such as bacteria, fungi, lichens and mosses.
The LSU AgCenter and the LSU College of Agriculture