Homegrown: Avoid 'topping' and other tips for pruning trees

The International Society of Arboriculture offered the following tips on proper pruning techniques for spring flowering trees:

 CHAMPAIGN, Ill.-One of the surest signs that warm weather is here to stay is the new blooms and buds on the trees around us. The beauty that lights up our backyards and gardens needs special care to remain prosperous. Pruning flowering trees has its own challenges, but the reward is great-health and brilliance!

"Flowering trees such as the crabapple, dogwood, Japanese maple, and cherry often require more frequent pruning," said Dr. Bruce Fraedrich, vice president of research at Bartlett Tree Research Laboratories.

Why is pruning necessary?

"These trees have a capacity for rapid growth, especially while they are young. They need to be pruned more often because they often grow in a confined space," Fraedrich said. Trees can be affected by dead, diseased, or broken branches. The removal of these branches improves the overall health and growth of the tree.

Pruning flowering trees may also be important in keeping your surroundings safe. Some branches can interfere with power lines, and poorly attached branches should be removed to avoid injury or damage to property.

"Before you ever start pruning, you need to know what you want to accomplish and why," Fraedrich said. "Decide whether the intent is to reduce the tree's size for safety reasons or for health reasons."

When should you prune?

Pruning at the wrong time can create imbalances and unnecessary decline in your tree's health. Summer flowering occurs on the new wood produced in the spring, while spring flowering occurs on the wood produced during the summer growth. Pruning for summer flowering plants and trees should take place in the late fall, after summer blooms, to establish a healthy growing environment for new buds. Pruning for spring flowering plants should take place after the plants have bloomed in early spring. If the tree or shrub is less than two years old, only light pruning is needed.

Helpful Hints

Fraedrich, also an International Society of Arboriculture Certified Arborist, warns against over-pruning small, flowering trees. "A homeowner should prune annually and lightly instead of pruning large portions all together. If a tree does become overgrown, the best thing is to reduce size over time instead of trying to solve the problem all at once."

The International Society of Arboriculture (ISA) suggest that you also follow sound pruning practices, such as making cuts just outside the branch collar to increase the chances of proper wound closure, avoiding leaving stubs, and keeping tools sharp and clean.

Avoid Topping

At times, a tree or plant needs to be pruned to avoid interfering with utility lines, buildings, or other aspects of the environment. In these cases, it is important to avoid the practice of topping, or the removal of all parts beyond a certain height with no consideration of the plant's structure or health. While many believe topping will reduce a hazard, it actually makes the tree more hazardous in the long run, and it is a temporary and ineffective solution.

Topping "starves" trees because leaves are responsible for creating food. In an act of defense, the tree creates shoots, which grow quickly and are prone to breaking. This can be especially hazardous in windy conditions, seeing as shoots can grow up to 20 feet in one year.

Topping also leaves a tree more susceptible to insects and disease, makes the tree aesthetically unpleasing, and exposes the tree to sunburn, which can lead to cankers, bark splitting, and branch death. It can also cause decay in wounds that cannot close.

The cost of restoring the tree's health is expensive, and topping often produces what Fraedrich calls "high maintenance trees."

Topping Alternatives

Fraedrich recommends reduction pruning as an effective alternative to topping. In this process, the size of longer branches is reduced using cuts back to lateral branches. Some branches can be removed at their point of origin.

Fraedrich also cautions against the "excessive thinning of interior branches." This can lead to excessive growth of upright interior shoots or to limb breakage.

Consulting an ISA Certified Arborist is a good way to learn how to manage flowering trees, especially if they are large. Knowledgeable arborists will not use topping on flowering trees.

"It can be difficult to know what cuts to make and how to handle a tree's size. Calling an arborist for the first two or three pruning cycles can really help homeowners learn how to maintain and care for their trees," Fraedrich said.

To find a listing of ISA Certified Arborists in your area and more tree care information, visit

www.treesaregood.org