White Birch Pruning

Tree Types

Of all the birch tree species grown in the United States, only a handful produce the vibrant white bark that is so ornamental. Cultivars of the European white birch (Betula pendula), Asian white birch (Betula platyphylla), Himalayan birch (Betula utilis) and the paper birch (Betula papyrifera) may require some pruning to remove dead or broken branches or to improve the branching structure in their rather upright, open-silhouetted canopies.

The ideal time to prune white birches is when the trees are dormant, anytime after the fall frost and through the winter. Dead branches may be cut away any time of year. Pruning birch trees in spring and summer poses many drawbacks. If pruned too late in winter and into spring, pruning wounds bleed large amounts of sap. This is not harmful to the tree, but it is alarming to the property owner. The sap also may stain the bark. Avoid pruning white birch trees from roughly mid-April to early August, as this is the time of year bronze birch borer beetles fly and lay eggs in trees. Trimming problematic branches in late summer is OK, but if possible, wait until later in fall after leaves begin to drop.

White birch trees generally require little pruning maintenance. Structural pruning while the tree is young and small leads to a better tree later on. Remove wayward branches from a birch tree, especially those that grow inward across the center of the tree canopy or rub against other branches or the main trunk. Branches with an attachment angle less than 30 degrees are much more prone to breaking. Remove such narrow-crotched branches early in the tree's life to develop the strongest branching structure and reduce the need for pruning years later to correct issues.

Do not use sealants or paints on pruning wounds. Sap bleeding is a natural response and prevents invasion of pathogens before the wound calluses and dries. Painting the wounds disrupts the timely callusing. For branches less than 3/4-inch in diameter, use a hand or bypass pruners. Branch thickness in the 3/4- to 1 1/2-inch range should be cut with a loppers. Larger branches require a pruning saw. Avoid pruning branches in a way that causes tearing bark or wounds that extend into the bark of the branch or trunk. Aim to make the pruning cut 1/4- to 1/2-inch above a leaf, lower branch or the trunk face.