Yonkers keeps its gardens on terraces, cut into hillsides that fall west toward the Hudson. Up at Untermyer the walled beds have held their lines for a century; down on ordinary blocks a lawn holds its line for a week, and that week is the work. 5 BROTHERS GARDEN & LAWN INC mows, edges and tends planting beds across the city's slopes, reading each yard for where the sun lands and where the shade sits all morning. June here smells like cut grass and warm stone by nine o'clock. The pleasure is in the last pass — the stripe laid straight, the border swept, the gate closed behind them.