We have an 18" border around our concrete patio. This border slopes down all around the patio and to complicate matters, we have a new puppy. Rather than put in small shrubs or flowers that the puppy would dig, I'm considering a small rock garden border aroung much of the patio. We'd be using rocks in the smallish to small medium range and rock garden flowers interspersed that tolerate a lot of sun. Anyone have any experience, confused suggestions or concerns about this idea?