September on the Sparta ridge opens cold and clears into blue, the hardwoods on Sparta Mountain just starting to turn at the top. East Mountain Services LLC keeps lawns on that high ground, where ledge breaks through the turf and every mowing line has to be planned around outcrop and root. Cutting, trimming, edging and cleanups take longer up here than on flat ground, and the payoff scales with the trouble, a sweep of mowed green running right up to bare gray rock. Sussex County can hand you frost at dawn and eighty degrees by three, so the schedule bends to the mountain instead of the other way around. At the end of a day like that the property looks like the woods stop exactly where they were told to.