Anyway, we let the grass grow a little taller than average, and go for native plants where possible... if it doesn't grow without care in Central Texas, it dies.
This year we had probably a couple of hundred sunflower plants come up volunteer, mostly in one little patch that grew to be about 7 feet tall. They were late bloomers, not showing with flowers until late May (well after Spring). Check out the before and after pics of the monster hedge here.
It isn't true that everything is bigger in Texas. These things don't hold a tiny candle to the monstrous midwestern beauties with giant flowers the size of a pizza, but they make up for it by making lots of little blooms.