The old Putnam rail line crosses Hawthorne as the North County Trailway now, a straight green seam under the trees where trains once ran. June mornings along it are all birdsong and wet grass, and that is the hour Green Jay Landscape Design is already out mowing, trimming and cutting borders back to a clean line. Yards in this part of Westchester are shaped things — beds, walls, panels of lawn set between them — and they read badly the moment an edge goes soft. Later in the year the route becomes cleanup: leaves off, beds tidied, everything squared away before the ground hardens. The reward is simple and it lasts the week — a lawn that looks drawn rather than merely cut.