Lichens on Azaleas: Harmless Indicators, Not Killers

Gray, flaky lichens on azalea trunks worry gardeners, but they're harmless. A lichen is a symbiosis of algae (food producer) and fungus (protection/moisture). They colonize when a plant's canopy thins, letting light reach bark—lichens signal stress, they don't cause it.

Scrubbing with a stiff brush removes them temporarily, but they'll return unless the underlying issue (deep shade, drought, poor nutrition) is fixed. Pruning to 12 inches in March can rejuvenate the canopy. As vigor returns and shade increases, lichens naturally disappear.