September in Watertown still runs stone walls through second-growth woods where hayfields used to lie, out toward the Bethlehem and Morris lines, and the lawns that took their place ask for tending. LawnKeepers LLC keeps them — mowing on a steady schedule, trimming close around posts and foundations, edging the walks, and clearing leaves once the oaks begin letting go. The name says most of it: a lawn is less a project than something you look after, one visit at a time. Late-season cuts go lower, the last cleanup goes thorough, and the yard heads into the cold tidy and ready. Lawn care through Watertown and the towns that border it.