Red Spiky Growth on Weeping Willow: Lichen or Decay Fungus?

Red, spiky, quarter-sized patches on a weeping willow are likely lichen “fruiting” (colorful during reproduction) or a decay fungus fruiting body.

How to Tell

Lichen: Bark underneath is solid. Harmless. Colors intensify when “flowering.”
Decay fungus: Wood under growth is soft/punky. Indicates internal decay—tree may hollow in 10–20 years, risking storm breakage.

No immediate threat. No treatment needed for either. Monitor structural integrity long-term if decay confirmed.

Plant Diseases: Weeping Willow with Bark Loss and Deformity: Internal Decay, Removal Advised; Weeping Willow Red Spiky Patches: Adventitious (Air) Roots, Not Borers—Harmless, Dry Up; Red Spikes on Willow Trunk? It’s Borer Frass—Here’s What to Do; Woodpecker Damage and Borer Infestation in Willow Trees; Black Canker on Weeping Willow: Pruning Over Costly Treatments; Lion's Mane Fungus on Willow: Decay Fungus in Hollow Trunk; Scale on Weeping Willow: Baking Soda Won’t Work—Use Proper Insecticide; Weeping Willow Decline: Roundup Drift vs. Borer Damage; Weeping Willow Borer Infestation: Identification and Treatment; Weeping Willow Near House & Drain: Root Concerns & Growth Regulators

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