Globe Willow with White Mold at Base: Decay Fungus Explained

Question: My globe willow has white mold in cracked, peeling bark near the ground. Is it dying? What should I do?

Answer

The "mold" is a fungal fruiting body (conk)—a sign of internal decay fungus. These fungi enter through bark wounds and slowly digest dead heartwood. They do not attack living sapwood or cambium, so the tree's health isn't directly threatened.

What This Means

• The tree can live decades with a hollow trunk, adding new sapwood each year.
• Risk arises only if major limbs become hollow and start breaking.
• No treatment can eliminate the fungus; the tree compartmentalizes it naturally.

Support Tree Vigor

Fertilize with 10-10-10 at 1 lb per inch of trunk diameter, scattered and watered in. Apply before rain to avoid extra watering. This strengthens the tree's ability to wall off decay and maintain structural integrity.

Monitor for large limb failures—if they occur and are hollow, consult an arborist for hazard assessment.