Canadian Hemlock in Hedge Defoliating Top-Down: Trunk Damage Likely

A 16-foot hemlock in a 15-year-old hedge has lost 65% of foliage from the top down since last fall; bottom is green with new growth. Neighbors are healthy.

Diagnosis: Trunk Injury or Borers

Melissa believes the most probable cause is damage to the trunk (mechanical, animal, weather) interrupting water flow. Borers are possible but less likely without exit holes.

Options

• Top will not regrow; removing it requires cutting and sealing with pruning paint—difficult on evergreens.
• Tree may survive but remain misshapen, out of sync with hedge.
• Best long-term solution: replace the tree to restore hedge uniformity.
• Optionally, transplant the struggling hemlock elsewhere to see if it recovers.