Announcement: Feel free to comment now, you should be able to do so.
Though this plant is native to the US, saying it's native to the Midwest prairies and water ways is more accurate. As the trend of planing natives in the garden grows I foresee this plant becoming a real problem this side of the Appalachian Mountains. It's already spreading like an invasive in New York water ways. And I've even found huge clumps of it at the community garden water way I visit.
Supposedly the seeds are loved by Goldfinches.
But then of course so are sunflowers, which have the benefit of being annuals and fairly easy to control. I couldn't get a patch of these started this year with the extreme heat the month of May brought. So hopefully the Cup Plant is as loved as it's said to be by these birds.
Bottom line, the second the Cup Plant goes invasive in my garden it's gone!