Black Walnut Sap on Treated Wood Arbor: No Damage

Building arbor under black walnut. Husband says sap damages treated wood. Owner asks truth.

Sap Does Not Damage Wood

Walnut sap contains hydrojuglone (oxidizes to juglone) which kills PLANTS (tomatoes, etc.) but wood is dead cells—no effect.

Juglone Facts

• In leaves, hulls, bark, roots.
• Toxic to sensitive plants under canopy.
• Persists years after tree removal.
• Does not affect lumber, treated wood, or structures.

Build the arbor. Sap is a non-issue for wood.