We've use Wet and Forget, but also use Mold Armour (green container, ready to just attach to a hose). Not tried on boulders, however, when washing down house (usually twice a year) we have sprayed the landscape blocks. They are very porous and do need more than just spraying like on the house. The landscape blocks do need some scrubbing with a broom or a stiff brush, so I think the boulders would require more work too.. just guessing. Have found if we wash the landscape blocks and a regular bases, or when we see it forming, of course it never gets out of control and requires actual work ! For mold on house, it just "melts" off with no effort. You might ask at your favorite hardware which product would be best on the landscape boulders. Good luck.

Bring some m& m's
 

sounds like a plan for

coffeebean...I have tried wet & forget on my hardscape, and it doesn't work on that. It does work on vinyl sided houses ( takes a while). Only powerwashing works on hardscape.

Green house
 

Wait till they go away and spray the house with wet and forget

and tell no one because no good deed goes unpunished

Just a note regarding Wet and Forget. I didn't get the type that hooks onto a hose, so I ended up with major cramps/soreness from squirting motion hundreds of times. It then took many days for the product to start working and didn't do a complete job. Maybe the hose product works better, but now I find just cleaning the mold with a sponge and bucket of water is instant, with great results.

It’s not mold.

Call community standards, need address

Have you talked to them? Possibly they are not aware of how bad it looks. A gentle suggestion might be all you need.
House-washing is a routine part of maintenance in this climate. Something many of us never dealt with before moving here. Best of luck.

I agree. In most cases, a good pressure washing of the house will remove most mold, mildew, and dirt. No need to use a special chemical.

But, I will point out, that after applying Wet and Forget, you were supposed to forget about it.

Yes.

We use "wet and forget" on our rental property house every fall. It does a great job of keeping the green stuff at bay. Blue bottle and just hook it on the hose. It reaches the high peaks very well.

I once used the interior Wet and Forget product on my shower stall. It was worthless.

Ask neighbors to help and clean the dirt off the house

Don't confuse mildew with mold. There is a health difference.