u/holylimptits

I am receiving native plants as a part of a lawn removal program. My plan is to remove all the sod pictured and use squeegee rock as mulch as it was suggested by the local program for our climate. My slope is about 1.5 to 2ft drop over 30ft. I’m struggling to figure out the best way to deal with the slope and prevent rock from going everywhere on the sidewalk. Would simple pound in edging be enough? Or should I be looking more toward a small retaining type wall such as railroad ties or similar?