Great success with planting a slope has to do with the types of plants you use. Here are some great tips, ideas and photos. For low maintenance, be sure to use drought tolerant plants!
side sloped backyard landscaping - Google Search:
Not the walls, but steps similar to what I have drawn in plan view so far Check out retaining wall projects from exceptionalstone.com!
Sloped Backyard Landscaping Ideas Pictures
Deck built onto sloped yard, railings
before & after ~ landscaping ~ adding a water feature and entertaining space into a sloping backyard area ~ landandwaterdesign.com
10 Stunning Landscape Ideas for a Sloped Yard (1)
DIY Garden Steps and Stairs • A round-up with great ideas & tutorials of step and stair projects for the garden and yard!
Deck on sloped yard