Swamped By Swamp Sunflowers?

This is a classic old-fashioned Southern passalong plant given to me many years ago by a dear lady in south Mississippi. It is a native perennial that is tougher than an Ole Miss quarterback and can flourish in any extreme soil, water, or weather condition known to the South. My little starter plant has multiplied into a background hedge at least 50 feet long and that is a good thing and just what I wanted it to do. I just pull out babies to keep them under control. Left alone these can grow up to 10 ft. tall, or they can be pruned in early summer to stay knee high if you prefer. They bloom only in late summer and early fall, and since I love yellow flowers I am happy with them.