> Personally, I think it's a quite attractive weed.

That's probably the reason why it got to the US in the first place. Germany now has a massive problem with these "weeds": https://en.wikipedia.org/wiki/Impatiens_glandulifera - looks nice in pictures, but it has a hard to describe smell that's very unpleasant. Fortunately it's not blanketing the entire landscape like stinknet in Arizona, but lately where I live it's everywhere in wet, shady clearings in forests, and also outcompeting native species.