This fungus began as a small patch in our driveway a year ago. Since then it has begun to take over. It looks and feels like seaweed. No smell but is slimy dark green. When there is moisture in the air, it grows. When dry, it shrivels up and seems to disappear but only until the moisture returns. Now that it's the rainy season here, it's rapidly spreading. So far it is only growing in the gravel and not the flower beds. It's really alien looking. Do not know how to get rid of it, nor do I know what it is? Is it harmful if it reaches the flower beds? In the picture the fungus is all the dark spots.
From what you've written about it (I can't really tell much from the picture either), it sounds like an algae. You could try getting a potassium soap (found in many commercial algae killers) and see if you can control the outbreaks with that.
I see this algae growth at one of the wholesale nurseries I use. They get huge slimy mats of the stuff, but that's mainly in the places that don't drain completely. Since they water twice daily, it can be a problem. If you can't get rid of it, I can check at the nursery to see what they do to try to control it. Copper sulfate should work.
meant to add that this person's driveway looks remarkably similar to mine...what they call a "tar & chip". this photo was taken the day the workmen finished this section. thankfully, the oily tar on the sides was worse than it looked. it dries almost instantly and after a couple of mowings, it was gone.
I can't say about the tar and chip drive; I've sprayed a tile patio with no problem except the odor. That disappeared after a few days.
If copper sulfate liquid has petrolium distillates, the you definately do not want to spray this on a driveway made from tar.
hi i have this problem and have been out ther hrs tryin to scrape it all up,its growing like mad at moment.i find if i rake it it just spreads the stuff everywer and grows faster in damp conditions,ive tried bleach ,worked for a bit.
did u solve it lummigirl?