Tree Root Oozing Sweet Liquid: Bacterial Wetwood (Slime Flux)

Diagnosing the Ooze

Yellow, sweet-smelling, bubbling liquid from a root wound with gnats swarming is classic bacterial wetwood (slime flux). Bacteria ferment sap inside the tree, producing gas pressure that forces frothy, alcoholic-smelling fluid out through cracks or wounds.

Key Characteristics

• Not a primary pathogen—opportunistic bacteria in anaerobic heartwood.
• Common in elm, maple, oak, mulberry, willow.
• Rarely kills tree but indicates internal decay or stress.
• Fluid is toxic to cambium—can kill bark where it flows.

Management

• No cure—bacteria are deep inside.
• Improve drainage/aeration around root zone.
• Do not seal wound—traps gas, worsens pressure.
• Divert flow with a loose pipe or trench to protect bark.
• Fertilize moderately to support vigor.

When to Test

County extension can culture samples to confirm bacteria, but visual/smell diagnosis is usually sufficient.