After Labor Day the traffic thins along the Bridgehampton road and the privet hedgerows go back to being what they are — tall green walls with quiet lanes running behind them. De Rosas Landscaping llc. likes September in Southampton: growth eases just enough to get ahead, and every cut holds a little longer. Mowing, trimming, edging and cleanups carry through the fall, with leaves gathered off the lawn before they mat down over the crown. Hedges are squared, beds are cleared, and the last warm afternoons make the work almost pleasant. A property that goes into October tidy comes out of March that much easier.