Algae is not a plant but an organism spread by spores.
Algae growing on roof shingles.
Black streaks green or white spots round lichens mosses green moss that spreads across your roof.
Although mold can grow in your roofing materials if water gets trapped somewhere if you see any of the following on top of your roof algae are more likely your problem.
Algae will grow flush against the shingles and fixtures on your roof.
A blue green algae known as gloeocapsa magma could be the reason you have the algae which is spread by airborne spores.
Commonly found in climates with warm humid summers it does no damage to the roofing but it certainly does looks bad.
Often algae that is identified as green when studied microscopically also looks black or quite dark on a roof surface.
Algae growth won t cause any structural problems to your roof but it looks ugly and it can damage the shingles over time.
It can be brown gray blue or green.
It appears on the shingles in streaks that head down the roof pitch vertically.
Algae growth is common on roof surfaces of several materials including asphalt shingles concrete and clay roof tiles and even slate.
Living in a humid area of the country like florida you ve probably seen your asphalt shingle roofs with unsightly dark streaks on them.