Where the Byram River finally gives itself up to the Sound, Greenwich keeps a rocky shoulder of shoreline, and March arrives there before it arrives anywhere else in town. A & S Landscaping Services works that western edge in both directions — mowing, edging and cleanups once the ground firms up, plowing and salting when the road glazes over. There is a plain satisfaction in a lawn cut down to one clean line along the walk, and another kind entirely in a driveway opened to bare pavement while the gulls are still arguing over the seawall. Snow here comes in wet and heavy off the water, so the work starts early and stays ahead of it. Come April the same properties want the winter raked out of them, and the crew simply changes tools.