Siding Fixed

Do you remember way back in February when some of my siding blew off?

Wind Storm 2/19/2016
Wind Storm 2/19/2016

Well, I fixed that. It took me a while to get around to it, as it often does with things I’m unfamiliar with. But, eventually I get around to such things. Finding a match for the siding wasn’t a problem, there’s a place over on Clyde Park (I don’t remember the name) that had a perfect match for my house color. I only picked up six pieces, figuring it’s close and I can always get more when I build my shed.
But even six pieces were enough to fix the side of my house and leave enough left to take care of the ugly bit on the back of the house. I took out that big metal hood fan in front of the window and patched it with foamboard when I started the laundry room, but that left a big hole in my siding.
realtor photo

Now it’s a nice cohesive whole. Anybody have any idea how to clean than green film off the bottom of the house? I’m going to try a pressure washer, but I feel like I need to add something to keep it from coming back.
patched the hole