“Late winter is the ideal time to prune most trees,” says Patti Nagai, UW-Extension Horticulture Educator. “It’s a time when insects and disease are not active, the growing season is approaching (allowing for wound closure), branches are visible, and the tree’s energy is still in storage.”
Pruning removes broken, diseased, or dead branches. Live branches are often pruned to shape or thin the tree’s crown and eliminate rubbing, downward growth, or competing branches.
Once April arrives, caution is the rule. Oak wilt, a deadly fungal disease among oaks, spreads easily when insects attracted to pruning wounds are carrying the fungus.
“It’s wise to consult a trained arborist for pruning during the growing season,” says Nagai, “to make sure you’re doing more good than harm.”