My neighbor has one growing on the edge of his property and gave me some seeds last year. He had no idea what it was. I planted them and have about 10 in my yard now. Someone told me it looked like a native wildflower, but I can't find it in any of my books or web searches. I'm just hoping it's not a non-native invasive plant (maybe that's why they're doing so good!) that I'll regret planting. The ones I have are about 6 ft. tall.