6:00am

Sat January 4, 2014
The Garden Report

Why Your Trees Will Thank You For Winter Pruning

Elm Trees Are More Resistant To Disease During Winter
Credit SriMesh/Wikimedia Creative Commons

Most certified arborists agree the dormant season is the time to prune trees. Leafless trees allow arborists easier, faster access to see what they are doing. Winter pruning also helps prevent the spread of disease.

Tom Throgmorton Explains How Winter Pruning Helps Prevent Disease

Trees store energy in other tissues once they lose their leaves. Any injury, like a pruning cut, becomes a priority for the stored energy. The plant uses the stored reserves to compartmentalize and close off that injury. During the winter most of the plant’s fuel can be directed at healing pruning cuts. 

The stored energy during the dormant season allows more time for wounds to close and harden-off from pruning cuts, preventing boring insects that spread Dutch-Elm disease from damaging elm trees.

Apple, mountain ash and pears should also only be pruned when they’re dormant because they are susceptible to fire-blight, which enters trees through open wounds. Winter pruning lets the wound close faster which reduces the risk of fire-blight infection. 

Maple, birch and walnut trees bleed sap when they’re pruned. While this may look messy, some studies show the heavy sap run may help the tree heal faster as sap acts as a natural wood preservative.

One exception to pruning in the winter is if the tree has several dead branches. The tree needs all of the live, sound branches it can keep for its own health. Pruning during the growing season makes it easier to decipher which branches are dead and which ones are alive.   

Many trees are neglected and only get pruned by nature during high wind storms or heavy snows. Studies show these trees are healthier and live longer when pruned to withstand storms.

Need some help? Contact a local, certified arborist to prune and maintain your tree investment.

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