When Is the Best Time to Trim Trees in Ontario?

Short answer: For most trees, late fall through winter, while they’re dormant and the leaves are off. Dead, broken or hanging branches can come off any time. Oaks should not be pruned from April to July, because of oak wilt.

Why Dormant Season Works Well

• You can see the structure clearly with the leaves off.
• The tree is resting, so pruning cuts put less stress on it.
• Insects and diseases are less active in the cold.
• Frozen ground can help protect lawns and garden beds from foot traffic.

Oak Trees: Avoid April to July

Oak wilt, a serious tree disease, has been found in Ontario. Beetles that spread it are drawn to fresh cuts on oaks in spring and early summer. The standard advice is not to prune oaks from April through July unless it’s an emergency.

Any Time of Year

• Dead branches: see deadwood removal.
• Broken or hanging limbs after a storm.
• Branches rubbing the roof or blocking a walkway.

Maples in Late Winter

Maples and birches can “bleed” sap if pruned in late winter and early spring. It looks alarming but generally doesn’t harm the tree.