On summer mornings the Huron runs a low ribbon of fog through Dexter-Huron Metropark, and the river-bottom lawns hold their dew a full hour longer than anything up on the bank. RIVER VALLEY works that valley ground — mowing on the schedule the grass sets, trimming out fence lines and awkward corners, edging so walks and drives keep a clean line. Mulch and bed care go in once spring dries enough to walk on, and cleanups carry off what the floodplain trees drop in October. Grass near a river grows hard and fast, and staying ahead of it is its own quiet contest. By afternoon the fog has burned away and the cut is still there, striped and even down to the water's edge.