Wildlife Gardening: What is this Berry Plant?, 1 by Blubird333

Blubird333 wrote:
I'm in Kansas and have this awesome "weed" that keeps spreading. It has a hollow stem and the clusters of berries start from a beautiful cascade of tiny white flowers that then turn into a cascade of dark blue/purple berries. It grows to about 5-6 feet each year. I'm trying to figure out what it is. It grows very fast, spreads easily and the birds love them. I have blue berry bird poops all over my yard from it. But I still love it. Anyone have any ideas?