Securing Rockery stones
If you are worried about your rockery stones falling over, you may want to consider using concrete at the back of the stones to secure them. I would suggest putting the stones in place and getting them into position. Once in position, they would need propping and any holes which the concrete might flow through filling in. Then pouring concrete down the back to secure the stones together and add weight to the rear of the stones so they don’t fall over. The pictures below show how we approached a project using large slender stones, where access was still required.