The old canal line runs the length of Hamden, straight as a ruler through Centerville, and by May it is a green corridor with lawns opening off it on both sides. CJK Landscaping LLC works those neighborhoods — mowing, string trimming, edging along walks and beds, and the cleanups that get a yard out of winter and into the season. Spring here arrives in a rush: the ground warms, the grass jumps, and staying on rotation is the difference between a lawn and a field. Nothing beats the look of a fresh first cut with the borders redrawn sharp. Hamden yards, kept even, week to week, right through to fall.