Weeping Cherry Oozing Black Tar: Slime Flux or Borers?

Black, tar-like ooze from a weeping cherry trunk suggests either slime flux (bacterial wetwood) or borer damage. Slime flux is foul-smelling, frothy, and not usually fatal. Borer sap is thicker, and indicates tree stress.

Diagnosis

• Slime flux: Oozes/drips, may be sudsy, smells yeasty/alcoholic. Bacteria ferment sap inside trunk.
• Borers: Sap from discrete holes; sawdust (frass) may be present. Tree stressed by drought, girdling roots, or deep planting.

Action Plan

1. Spray trunk with Merit (imidacloprid) if borers suspected.
2. Deep-root fertilize (10-10-10 at 1 lb/inch trunk diameter) in spring, mid-summer, fall.
3. Prune dead tips; check for girdling roots at base.
4. If slime flux: keep tree healthy—it may outgrow it.

Replanting After Removal

If tree dies, no soil treatment needed. Replant directly in same spot.

Expert Help

Contact Alabama Cooperative Extension, C. Beaty Hanna Center: aces.edu