|I have a steep|
|Black-eyed Susan is an excellent choice for a hot, sunny slope. Dianthus gratianopolitanus ?Feuerhexe? (Firewitch), also called Cheddar Pinks are evergreen perennials, or you might try Peony or Shasta Daisy. Each of these plants will develop into a green mound with the bonus of some colorful flowers. Or, how about some ornamental grasses? Depending upon which you choose you'll have clumps of green or blue-green or even reddish foliage in a fountain shape.
Best wishes with your garden!