Ponte Vedra Beach lives between two kinds of water, the Atlantic pounding its dunes on one side and the slow tidal marsh of the Guana and Tolomato rivers on the other. In fall the nor'easters arrive with gray skies and salt carried on the wind, and every lawn beneath the live oaks feels it. Defenders lives up to its name in that weather, standing watch over turf that has to hold its ground against thin sandy soil, salt spray and the long shade of moss-hung branches. The work is the patient kind: mowing that suits the coast, keeping edges true along the drive, clearing whatever the wind leaves behind, so the grass comes through each blow green and upright. When the sky clears and the light comes back off the ocean, a defended lawn looks as though it never flinched.