Trimming lawn edges keeps the grass looking neat and prevents it from spreading beyond its border. For best results, lawn edges should be re-cut each spring. Edge lawn around sidewalks, driveways, gardens, trees, and shrubs. Pro Tip: For a straight edge, cut against a plank of wood; for a curve, trim along a rope laid on the ground. Remove excess soil to leave a vertical edge measuring 2-3″ (5-7.5cm) deep. Install edging If desired.