I'd like to combine a dry stack wall with growing alpines and plants that like dry conditions. My idea is to build a wide wall - maybe 3 ft wide. Rocks on the front side and on the back side. Basically two dry stack walls close together. Then fill the resulting space between the stones with sand and soil for planting.

Larger stones would bridge the two walls for support. The wall would be about 3 ft tall and free standing.

Has anyone done this? Any special suggestions for such a wall?