It's a Maryland native (as you can tell by the name!) It's hard to propagate from cuttings which is probably why it isn't more widely available. The two plants I bought probably 8 years ago were from Plant Delights in NC. They bloom heavily in early summer and continue off and on until frost. Striking and tidy plants. I finally spotted a few volunteers this year, but they don't spread as nicely as I'd like. Excellent plant - impervious to insects and diseases in my experience.