Last year, I covered a large section of my yard with mulch, and put in a
number of plants and shrubs. This year, I've had a few things pop up from
the mulch, that I can only describe as "puff balls." They seem to be some
kind of mold; they have a soft skin that turns yellow under the hose, and
inside they are full of black, powdery stuff that blows away quickly when
exposed. Anybody have an idea what this is, or how to get rid of it?