Manalapan Brook runs the length of Jamesburg, low and unhurried in July, and the yards along it hold their green a little longer than most through the heat. A&R Landscaping LLC keeps a steady weekly rhythm all those months — mowing at a height that shades its own roots, trimming the tall growth at the fence, finishing before the afternoon peaks. In a borough less than a mile across, the same lawns come around often enough that the crew knows each one's habits. Cleanups take care of the ends of the year, when the brook runs high in spring and the maples give it all up in fall. What is left behind each visit is a lawn that looks finished rather than simply cut.