Thirty years ago I found this plant growing by the side of a building and brought a baby of it home. Despite my efforts to contain it to one small area, it spread to all sides of our acreage, and seeds unwittingly wound up in a lot of other plants that I was giving to friends.
I always felt so guilty when I saw that they had kept these invaders. I would always warn them about how invasive they were and they would laugh at me and say they thought they were so pretty. I still feel badly about letting this scourge loose in our area.