what is white mold under leaves surrounding my hydrangeas?

i found white mold or mold-like stuff around the base of my hydrangeas when I was cleaning leaves away from them. I've been told this is not healthy stuff, but I can't remember what it is and can't find reference to it. Can someone identify?

thanks

Hi there, just saw your post. I would think just regular mold. How does the plant base look? Post your thread on the Hydrangea forum. There are some real expetrts there. I'm going to blow away all my leaves in yard this weekend. Wonder what I will find. Maybe the spot is too wet, no sun at all?
Good luck

thanks tuliplady.