This is an invasive plant in Washington. It spreads by seed, so it would be a good idea to deadhead before the seeds form if it is a problem in your locale. I would like to have one in my herb garden for medicinal purposes, and thus far my county has not had a serious infestation so I believe I can manage this cautiously.
I let mine go to seed.. and it pooped out .. no babies.. no sign of them anywhere .. our real cold winter last year paid a toll on quite a few plants.. this one was of them unfortunately
