Snowballs in July

The other day, Cop Car was asking if she was seeing a "snowball" in one of the pictures I posted. After my so cleaverly saying, "duh, what", she added that she meant a hyranrangea, also known as "snowball bush".

I know that a certain vibernum is often called snowball bush, but didn't realize that other people called hydrangeas the same thing.

Then came this thread on the Gardenweb, which showed that other people have the same confusion in discussions of snowball bushes. Also check out the link that Georgia-Rose provides to the Cobb County Cooperative Extension that pretty much sums up the differences.