By early afternoon in July the heat stands in sheets over Jefferson Avenue, and the lawns set back from it go pale and thirsty at the edges. BladeEdge Outdoor Lawn Services keeps working right through that hour, mowing at a height that shades the roots and trimming close along fences, posts and mailbox stands. The edge beside a driveway is the part people see from the car, so it is cut clean and straight, a thin dark seam between concrete and green. Clippings get blown back off the pavement rather than left to bake. When the sun finally drops toward the water, the whole block looks like someone paid it attention.