February is time to prune crape myrtles
Published: Saturday, January 21, 2012 at 6:01 a.m.
Last Modified: Tuesday, January 17, 2012 at 4:53 p.m.
In thinking about pruning crape myrtle plants, as with many landscape features, an old adage comes to mind: "Beauty is in the eye of the beholder."
In essence, if it's your landscape, do what you want. If you are happy with the results and it is not harmful to the environment, take the feedback of others with a grain of salt.
Occasionally the Extension Service receives inquiries from landscapers and homeowners who have heard varying perspectives about when crape myrtles should be pruned, as well as the extent of pruning that should be employed. Research at the University of Florida has indicated the optimum time to prune is February. This time of year, plants have not yet begun to set buds for the summer flowering season, yet we are far enough into the winter that by the time plants recover from pruning and begin to break dormancy, the danger of damage from severe cold is past.
The extent of pruning is a much broader topic, and there is little consensus in the industry about how much pruning should be done — or whether pruning is needed at all. Perhaps the place to begin is where there may be some common ground. I like to stand back from my plants before starting to prune to get a full view of the plant. Check for any crossing branches and plan to remove one of these, as their rubbing during windy days scrapes away the bark surface — as well as the protection the bark affords. If any obvious dead branches exist, these should be removed.
Next, examine the base of the plant and remove any canes that have suckered from the base during the past growing year. Examine the base, with future growth in mind, to determine if canes are going to overcrowd one another as the plant continues to grow; better to remove these to allow for future growth sooner, rather than later.
Beyond this, opinions vary greatly about what should be done in the way of pruning. Commercial landscapers regularly make severe cuts on crape myrtles, removing all that is more than three feet above the ground. Often this is done for expediency sake, for it takes less than a minute and the job is done. Sometimes, this is done because people see it and assume this is the necessary and proper way to prune crape myrtles. Sometimes, it is done because the plant has outgrown the site and it is necessary to keep growth in check. In reality, we must ask if it is really necessary — many times not pruning at all will result in a better plant shape and form.
Most trees have two types of buds. Those at the end of the branch are called dominant or apical buds. A second type of bud also exists along the branch, known as lateral buds. Lateral buds are inhibited by the dominant growth of the apical buds, but become active when the apical bud is removed — in storms, by pruning or by any other action. It is nature's way of protecting the life of the tree — a means of helping it recover from damage. Removal of the dominant bud results in the sucker growth often observed in tree branches. When severe pruning cuts are made to crape myrtles, several of these lateral buds become active and their emergence creates a multi-branched growth, all at the site of the pruning cut. These suckering branches give thick growth, which appeals to many. However, several of these grow toward the interior of the plant resulting in crowding and poor air movement, which sometimes leads to other problems. Moreover, these are often weakly attached to the main stem and may break during summer storms. It is the opinion of some that the plant's reaction to severe pruning results in a deformed shape and structure that is difficult to correct.
Perhaps a better approach would be light pruning, which, beyond cuts to remove crossing and dead branches, might include removal of any branches growing toward the interior of the plant, to allow better air movement and light penetration. This will protect the shape of the plant while still meeting the corrective measures necessary for good form as a shrub or small tree. Over a period of years, this annual examination and subsequent pruning will result in a well-formed shrub or small tree.
The most impressive crape myrtles I have seen in Florida were planted in a nursery, several on either side of a straight driveway for a run of 60 or 80 yards. These overarched the road, creating a canopied avenue, of impressive appearance. When I asked the nursery owner about them, he responded they were 20 years old and had never been pruned. The overall form of the trees, the beauty of the large trunks, the fact that at planting they had been spaced well apart with future growth in mind, and the thriving condition of the plants convinced me that if it became a question of whether to prune severely or not prune at all, not pruning is definitely the better choice. But again, beauty is in the eye of the beholder, and obviously there are many who prefer the appearance rendered by the emergence of multiple lateral buds. Their plant, their choice.
David Holmes is Marion County extension director. Contact him at firstname.lastname@example.org.