Bacterial Wetwood (Slime Flux) in Mulberry: What You Need to Know

Foul-Smelling, Wet Soil at Tree Base? Likely Bacterial Wetwood

Bacterial wetwood (slime flux) is a common condition in mulberry, elm, maple, and other shade trees. Bacteria ferment in the heartwood, producing gas pressure that forces foul-smelling, slimy liquid out through cracks, wounds, or root flares.

Key Symptoms

• Wet, dark streaks on bark or roots
• Foamy, foul-smelling ooze at base or branch crotches
• White/gray crust when slime dries
• Grass or plants killed where slime drips
• Tree canopy often appears healthy

Cause and Progression

• Caused by anaerobic bacteria (Enterobacter, Klebsiella, Pseudomonas) in heartwood.
• Not a decay fungus; infected wood resists rot due to high pH.
• Triggered by stress: drought, heat, wounds, soil compaction.
• May persist for years; rarely kills the tree directly.

Management

• No cure exists. Do not drill drain holes—this spreads bacteria.
• Reduce stress: Water deeply during drought; mulch root zone.
• Fertilize only if deficient based on soil test.
• Disinfect tools with 10% bleach after working near affected area.
• Remove loose bark in flux area; let dry. No wound dressing.
• Flush with dilute bleach (1:9) to reduce odor and insects.

Long-Term Outlook

The tree can live for decades with wetwood. Structural integrity is usually unaffected unless decay fungi enter through separate wounds. Monitor for canopy decline, which may indicate additional problems.

Focus on overall tree vitality rather than trying to stop the flux.