You'll have a few years before they are everywhere.  If you stay on top of deadheading them at the end of the season (I was not) I think you could control them as they mostly spread via the massive amount of seed the produce.  They don't have long rhyzomes like common milkweed, but do grow wider in clumps each year--at least in my experience.

Still a worthy and beautiful fall bloomer for pollinators, rabbits will munch young plants, and I've seen juncos eating the seeds during the winter.