My usual farmer at the farmer's market was selling it this week. I didn't know what it was. When I asked, he told me then said, if I hadn't had it before, I shouldn't get it. I took his word for it.
I just sigh deeply and let the dang thing grow. Because once it berries out, the cardinals love it. Kind of like the dandelions, because the chickens love dandelions. I just let them grow, it's a LOT easier than trying to pull them!