September in Riverside: the Mianus runs brackish and slow past the boat slips, the light turns the color of cider, and lawns finally grow for pleasure again instead of survival. Greens Landscaping Service works this stretch of Greenwich with mower, trimmer and edger — the ordinary tools that add up to a yard somebody wants to stand in. Salt air is hard on turf this close to the water, so the schedule bends around it. Fall cleanup here means leaves off the grass before the first hard rain glues them down, and beds cleared for the cold. There is real pride in the last cut of the year, the one that has to hold until spring.