Spring arrives in Wassaic along the Ten Mile River first, the water high and cold, the rail trail muddy, the hills of the Harlem Valley going green from the bottom up. Nature's edge landscape starts its mowing season there, on properties where lawn gives way quickly to meadow, brush and stone wall. The work is about holding a good line between the two — mown grass kept even and trimmed close, the wild edge respected rather than erased. Through summer that means steady cutting, edging drives and paths, and keeping a place looking deliberate without looking scrubbed. In a valley this beautiful, the lawn only has to hold up its end.