Recovering Willow from Herbicide-Induced Yellowing

Diagnosing the Cause

Yellowing weeping willow leaves after a "weed and feed" (fertilizer + herbicide) application strongly suggests herbicide injury. Broadleaf weed killers (2,4-D, dicamba, MCPP) volatilize or leach into root zones, damaging non-target trees. Willows are especially sensitive.

Remediation Steps

1. Dilute the herbicide: Water deeply every other day for one week—apply 1 inch per session (measure with a pan).
2. Then water weekly: 1 inch per week if no rain.
3. Do not fertilize until the tree shows recovery.
4. Monitor for leaf drop: Hardwoods often defoliate and releaf if roots survive.

Assessing Tree Viability

Perform the scratch test on several branches:

• Scrape bark with a knife: Green = alive; Brown = dead at that point.
• Work downward from branch tips until you find green tissue.
• If no green found on any branch, the tree may be dead.

Prevention for the Future

• Never use "weed and feed" within the drip line of trees.
• Spot-treat weeds with targeted herbicide, or hand-pull.
• Use mulch rings to suppress weeds without chemicals.

Timeline

Recovery may take weeks to months. If the tree leafs out next spring, it survived. If not, replacement may be necessary.