Boy, you do have problems with clay slopes in North Carolina. We did a quick scan of previous Mr. Smarty Plant questions on this subject and found several that had good answers and even plant lists, and all from North Carolina.
Durham, NC - Durham County, very close to Wake and Chatham Counties
Cary, NC - Wake and Chatham Counties
Charlotte, in Mecklenburg County, is on the central southern border of North Carolina with South Carolina.
So, we're thinking that the plant lists and instructions on the previous questions should be of help to you, and we won't be repeating ourselves. As for making them grow, you have made a vital first step in using plants native to the region. Follow each plant link on the lists of plants to our webpage on that plant, and read how much moisture, sunlight, etc. it needs and place the plants accordingly in your garden.