Hillsborough Tree Board Says: ‘Stop Topping Crape Myrtles’
The Hillsborough Tree Board is on a mission to get people to stop topping crape myrtles and other trees.
The widespread procedure — also called heading — involves arbitrarily cutting vertical branches to stubs at a uniform height. The practice is used primarily to reduce a crape myrtle’s size. However, this type of pruning is unnecessary and harmful to the trees. In addition, branches often grow back higher and bushier than the original.
Reasons to Stop Topping
- They Starve — Because leaves are a tree’s food manufacturers, removing them can starve the tree. Topping triggers the rapid growth of multiple shoots below each cut. If a tree does not have the energy reserves to grow this abundant crop, it will weaken and may die.
- They Rot — Topping creates multiple stubs with wounds that the tree may not be able to close. This invites organisms and pests that can rot a tree. A tree can defend itself from rot when side branches are removed, but it has a hard time walling off so many severe wounds.
- Their Limbs Weaken — Limbs made from new shoots grow quickly, are weakly attached and break easily in windy conditions. A regrown limb never has the structural integrity of the original.
- Their Wind Resistance Increases — The thick growth of sprouts, which results from topping, makes a tree top-heavy and more likely to be blown down by wind in a storm.
- They Get Sunburns — Removing the leaves of a tree’s crown exposes the remaining branches and trunk to full sunlight and heat. Bark tissues suddenly exposed to the sun may be burned, damaged or killed or may develop disease cankers.
- They Are Ugly — Topping has no regard for a tree’s structure or growth. A crape myrtle that has been topped can never regain its natural form.
- It Is Expensive — Topping is a high-maintenance pruning practice with hidden costs. If a tree survives topping, it soon will require pruning again or a storm may destroy the weakened tree, prompting a need to remove and replace it. Topped trees are prone to breaking, making them hazardous and adding potential liability costs.
Proper pruning techniques can remove excessive growth without the problems of topping. Such pruning uses the fewest cuts possible to remove the most wood and respects the plant’s natural shape.
The best time to prune crape myrtles (Lagerstroemia indica) is during the winter while they are dormant. It is easier to see their branching structure then and to identify the limbs that are to be cut off. Crape myrtles, however, can be pruned year-round to remove unwanted branches and basal sprouts.
When a tree becomes too dense, the offending branch should be cut to its point of origin. Make each cut at the junction with another branch or just outside the branch collar to remove the whole limb. If a branch is to be shortened only, make a sharp, clean cut just beyond a lateral bud that faces out from the center of the tree. Visit the Web page www.arborday.org/trees/NineNum3.cfm for images.
To make a crape myrtle shorter, reach inside the plant to find the leading branches that are the longest. Prune those branches to shorter laterals or to the ground to thin and reduce at the same time. By making a number of these cuts, the tree’s height can be lowered. A tree that has become too wide can be pruned in the same way.
Mature, established crape myrtles do not require annual pruning. However, the internal branching can be thinned to open the plant's canopy, which will not modify its original shape.
The best way to prevent the need for significant pruning is properly selecting and placing crape myrtle cultivars in the landscape.
Topping is considered an unacceptable practice by professional organizations such as the International Society of Arboriculture and the National Arborist Association. Before hiring a tree service, the Hillsborough Tree Board advises investigating services to find those that do not advocate topping.
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