First course: concrete blocks.

This may make things easier to visualize. Now we can see the form that the raised planter is going to take. See? It curves! Curves and stucco are fantastic (I said this before and no I will not be getting over it anytime soon). Think about those houses in Santa Fae that have the adobe style and all the interior features are curved. It's great I tell you! In a garden they catch the light and show off the texture of the materials as the sun passes during the day.
So you have to visualize this at seat height with stone caps and rich saturated stucco walls. There will be plants too. It's gonna be great, and I will keep y'all posted on the progress.

Thanks for your comments everyone :)