One possibility is to use a Morph for the wall cap (all of the brick portion) and then have a river rock textured wall below trimmed by the cap... with a separate bit of wall that is textured with brick at the driveway as shown for the end condition.
To get the three materials that I see, the wall cap would have 3 different fills extruded for the Morph to get the 3 different brick textures assigned to the extrusion. I found this YouTube tutorial for how to extrude a Morph profile along a 3D path to get the curves shown in your image:
https://youtu.be/XsdOBD_MGvA
