Lichens on Miniature Acer: Harmless but Indicative

Gray/White Scaly Growth on Trunk and Branches

A miniature green Acer shrub has gray-white scaly patches on the main trunk and branches, some of which are dead. The owner fears disease.

Expert Identification

The growths are lichens—a symbiosis of fungi and algae. They are not parasites and do not cause disease. They commonly appear on older, declining plants, rocks, fences, and even power lines. Shaded areas are more prone.

What It Means

Lichens indicate the plant is already stressed or declining for other reasons (e.g., root issues, poor soil, age). They are a symptom, not the cause.

Action

Focus on improving the shrub’s overall health: proper watering, fertilization, and sunlight. Do not treat the lichens directly.