West of Atlanta the ground around Bill Arp rolls in long low waves of red clay and pine, creek bottoms folded down between the ridges and Sweetwater Creek working its way through the county. Spring arrives early on those slopes, and a lawn on a grade needs a steady hand to keep it even from top to bottom. GrassRoots Turf of McDonough handles that with mowing, trimming the banks and fence lines, edging the drive, and clearing every clipping off the pavement. A hillside yard cut level looks twice the size it is. The rounds run through the season for homes around Bill Arp.