Stand at Harbor Island on a clear morning and the Sound goes a blue you never get inland, masts ticking, gulls arguing over the breakwater. Blue Lawn, Inc. keeps lawns on the streets that run back from that water — mowing, edging, trimming, and the cleanups that bookend the growing season. Salt air and shore wind are part of the growing conditions here, and grass this close to the harbor asks for attention rather than a formula. A finished lawn should look the way the water looks on a calm day: even all the way across, with a clean line where it ends. That is what we are after, week after week, in Mamaroneck and the villages beside it.