Milstead's old mill houses sit in tight rows with small, particular yards, and a small yard shows every mistake. The Lawn Mowing Doctor takes those on with the same care as the wide lots out on the county roads: even height, edges cut where they belong, walkways left clear. July in Rockdale is heavy — the air thick by nine, thunder somewhere by four — so the mowing gets done early, while the grass is still standing up. Cut on a steady rhythm, turf holds its color through that heat and crowds out most of what it does not want. Milstead, Conyers and the streets north of town make up the round.