Briarcliff Manor sits up on its ridge with the Hudson glinting through the trees below, and in October that whole hillside goes copper from the old aqueduct trail down to the river road. Tom Williamson Landscaping, Inc keeps the properties along those winding lanes in order: mowing and edging through the season, trimming and hedge work, mulch in the beds, spring cleanups and the long leaf haul that autumn insists upon. Yards here tilt and terrace and hide behind stone walls, so the work is done by hand as often as by machine, and it shows in the corners. Winter brings the wet, heavy snow of the river valley, and with it plowing, shoveling of walks and stairs, and salting the steep drives that run down toward Scarborough and Ossining. Ground kept in order on that ridge looks as though it simply happened — which takes a great deal of showing up.