On Sun, 28 Jun 2009 07:26:51 -0700 (PDT), BradMM
wrote:

I planted a wisteria on the west side window to an out building where
my office and tool room are. Because it's been 108 degrees this week
and we just replaced our compressor/fan, I thought about growing the
wisteria OVER this building's roof. Then I noticed that there appears
to be mold growing under the wisteria that's there. I guess this
makes sense for mold to be growing in an area of reduced air movement
due to the dense plant being these... right?

Most likely. Mold can not grow without moisture and something to feed
on. Get rid of the moisture and increase air circulation. UV rays
kill mold too.