Old stone walls run through half the yards in Middleton, and a lawn is only ever as finished as the line where it meets one. SteveSalisburyTreeServices works that line — mowing first, then trimming right up against the granite, edging the beds so the border reads crisp instead of blurred. Late-summer afternoons here, after a thunderstorm has come through and gone off east toward Emerson Brook, the grass is soaked and glossy and the whole street smells green. Mowing is heavier going on a day like that; the stripes come out beautifully anyway. Careful passes, one property at a time, and a yard handed back better than it was that morning.