Vine Maple Lichen and Leaf Spots: Separating Cosmetic from Serious

Lichen on Bark: Harmless Epiphyte

The "moss" on your vine maple trunks is lichen—a fungus-alga partnership. It:

• Does not parasitize the tree.
• Indicates clean air and good light exposure.
• Thrives on thin canopies (more sun on bark).
• Requires no treatment—leave it.

Yellowish-Brown Leaf Spots: Likely Fungal

Spots on leaves suggest anthracnose or leaf spot fungi—common in wet Northwest springs. They rarely kill trees but can cause early defoliation.

Recommended Actions

• Rake and destroy fallen leaves to reduce spores.
• Improve air flow by pruning crowded branches.
• Fertilize with 10-10-10 at 1 lb per inch trunk diameter to boost vigor and canopy density (which shades out lichen naturally).
• Avoid overhead watering.

Baking Soda Myth

Home remedies (baking soda sprays) are unproven for lichen and impractical at scale. Copper fungicides may reduce lichen incidentally but aren't labeled for it.

Leaning Trees

Leaning may indicate root instability or phototropism. Stake young trees if needed; assess root plate for lifting.