Weeping Willow Decline: Roundup Drift vs. Borer Damage

Two distinct issues may be affecting your 2-year-old weeping willow:

1. Roundup (Glyphosate) Drift

• Symptoms: Leaf yellowing, curling, browning, drop within days of application.
• Drift from 6 feet away is plausible—willows are highly sensitive.
• Damage is usually to foliage only; roots may survive.

2. Borer Damage (The 6mm Hole)

• Round hole at base = likely clearwing borer or carpenterworm entry/exit.
• Frass (sawdust) may be present.
• Borers attack stressed trees—Roundup damage could have invited them.

Diagnosis Steps

1. Scratch test: Scrape bark on upper branches. Green = alive; brown = dead at that point. Work down to find live tissue.
2. Inspect the hole: Probe gently. Fresh frass = active borers.
3. Check for new buds at base or on lower trunk.

Action Plan

• If green tissue found: Prune dead wood, water deeply weekly, mulch. Tree may resprout.
• If all brown: Tree is dead. Remove it.
• Do not replant in same spot if borers confirmed—larvae may persist in soil/roots.
• Future: Never use Roundup near desirable trees. Use shielded spot treatment or hand-pull weeds.

Willows are tough resprouters. If roots survive, it may return from the base.