Hemlock Decline from Ground Up: Woolly Adelgid Likely; Topping Delays Inevitable

Thirty 12-ft hemlocks dying from the base upward; at 6 ft they’re bare but hold dead needles. Owner asks if topping in spring will force sprouts on bare trunks.

Grim Prognosis

Bottom-up death signals root/vascular failure, not drought (which kills top-down). Hemlock woolly adelgid (Adelges tsugae) is the prime suspect in this region.

Topping Consequence

Cutting tops may force epicormic shoots at the base, but the underlying pest/pathogen remains. The new growth will simply be attacked again. You buy time, not a cure.

Only Real Option

Call your county extension immediately for adelgid scouting. If confirmed, systemic imidacloprid or dinotefuran (professional application) can suppress populations. Without treatment, loss of the stand is near-certain.