By mid-June the humidity sits heavy over Farmington Hills and the grass outruns everybody — an inch on Tuesday, another one by Friday. Yorkie Brothers Lawn Care LLC keeps pace with it. Mowing, trimming, edging, clippings cleared off the drive, week in and week out through the long green middle of an Oakland County summer. Out past the lawns around the Longacre House on Farmington Road, whole streets go their own shade of deep green in July, and a yard that is kept looks it from the car and looks better still from the back step at dusk. A clean edge is a small thing. It changes the whole face of a house.