Being in NC means you are in one of the best places to buy your plants
relatively locally. The North Carolina Association of Nurserymen can probably
give you info about growers in your area that specialize in the plants you
seek. Also, many garden clubs in the state hold plant sales where "babies" are
sold to raise money for scholarships or garden improvement in the state. For
example, the Raleigh Garden Club will be holding its sale Apr 9-11 at the State
Fairgrounds. Many of the botanical gardens sell native plants (UNC Botanical
Garden in Chapel Hill does, I know.) There are such gardens in the Charlotte
and Boone areas. If you'll give me more specific info about your location,
maybe I can find more local sources for you.

Happy gardening...it can be done in Carolina clay.