Globe Willow Oozing Frothy Sap: Diagnosing Frothy Flux Disease

Not Borers—It's Frothy Flux

The splitting bark, copious sap flow, and foaming on your globe willow indicate frothy flux—a yeast-driven fermentation of cambial tissue, distinct from bacterial wetwood (slime flux) of elms/ash. It enters through wounds (freeze cracks, pruning, mower damage) and ferments inner bark.

Frothy Flux vs. Bacterial Wetwood

Feature	Frothy Flux	Bacterial Wetwood
Location	Cambium/inner bark (shallow)	Heartwood (deep)
Cause	Yeast/saprophyte fermentation	Bacterial fermentation
Hosts	Willow, poplar, aspen	Elm, ash, hackberry, maple
Appearance	Frothy, active bubbling	Slimy, slow ooze

Management: No Spray Cure Exists

Surgical Option (If Localized)

1. Mix 10% bleach solution (1:9 bleach:water).
2. Cut out all discolored bark to hard wood.
3. Sterilize knife in bleach after every cut.
4. Soak wound with bleach solution.
5. Leave open—no paint, wrap, or sealant.
6. Never remove >50% circumference—remove entire branch instead.

Cultural Vigor Program (Essential)

• Water deeply: 1 inch weekly, let soil dry slightly between.
• Moderate fertilization: Balanced fertilizer (Miracle-Gro, Peter's, or lawn fertilizer) —avoid excess N.
• Prevent wounds: Mulch ring eliminates mower/trimmer damage.

Long-Term Reality

Frothy flux waxes and wanes for years. Healthy trees often outgrow it. Focus on vigor—willows tolerate drought better than assumed. Coexistence is common.