Piedmont

The Piedmont is the rolling upland between the Appalachians and the coastal plain, covering Atlanta, Charlotte, Raleigh, Greensboro, and Greenville. Red clay is the defining feature here: it holds water, drains slowly, and sets up hard, which is why so many conventional plantings sulk through their first summer. Natives such as white wild indigo, heart-leaf foamflower, and sweetbay magnolia are adapted to that clay and to long humid heat.

Conditions: Deep red clay soils, 45–50 inches of rain through the year, hot humid summers, mild winters with occasional hard freezes.

Cities and areas: Atlanta, Charlotte, Raleigh, Greensboro, Greenville, Durham.