Slime Flux (Wetwood) on Cherry Trees: What That Oozing Sap Means

Identifying the Problem

The foul-smelling, sticky sap oozing from your cherry trunk—with ants feeding on it—is classic slime flux (wetwood), a bacterial condition common in many hardwoods including cherry, elm, maple, and oak.

Cause and Progression

Fermenting bacteria in heartwood produce gas pressure that forces sap through cracks or wounds. The flux darkens on air exposure, attracts insects, and may stunt nearby foliage if prolonged. However, it rarely kills the tree.

Management

• Do not install drain pipes—they worsen internal decay.
• Remove loose bark in the affected area and let it dry.
• Wash the trunk with a 1:8 bleach solution to deter insects and reduce odor.
• Avoid wound dressings.

Long-Term Outlook

Fluxing often stops spontaneously. Maintain tree vigor with proper watering and minimal root disturbance. The condition is cosmetic, not fatal.