John I saved some pieces of old driveway and garage; concrete-slab. I'm not sure what these here are but that's what I will use for the same application.
In this example, the fence also relates to the surrounding plantings as it weaves through it. Like the waving grasses in this garden, the fence seems to say that this home is relaxed and easy going.
I like the growth between the stones, the colors (although not necessary) and the relaxed, unfussy look. Mostly I think it would serve as hard scape for the dogs to walk on before entering the house and bringing in mud.