Tom,
Be careful where you plant them. They reseed, and even though they supposedly aren't winter-hardy above zone 6, the roots survive the winters here and I'm sure the roots are spreading as well as the seeds.
I've been trying to get them under control for years. I don't really want to get rid of them completely, but they come up everywhere and I only want a few, not a whole yard full. When I see advice that mentions solanaceous weeds, nightshade and Chinese Lanterns are the first weeds that come to mind.
