Japanese knotweed??

Butterfly Bush?

I think herbalbetty is right, if it's what grows around here next to streambeds. I drive by big bushes of it that grow alongside the creek I drive past while going to work.

Here is a link that might be useful: Info and picture of Japanese Knotweed

Knotweed is a horrible, invasive pest and almost impossible to eradicate. It's also called Japanese bamboo, thereby slandering the bamboo family. You can try round-up but it will require persistence. My sister smothered it by putting a tarp over the patch and leaving it on for a year - and spraying roundup on anything that crept out from under.
This rivals purple loosestrife as an invasive and should be destroyed when seen.

Thanks everyone-- I looked it up, and it definitely is knotweed that I'm asking about -- you know, I thought it was weird that all of a sudden, I saw this everywhere-- and to think that I imagined it might be good for a "problem area" I have-- whew! It's a good thing I asked! It could have taken over my property! --Hobbes