The Shawsheen River threads north through Billerica, low and shaded, and the yards along it hold their morning damp long after the sun is up. Meadowlark Landscape Services mows into that hour, when the grass cuts cleanest and the stripes lie down straight. Trimming around old stone steps, edging where the bed meets the turf, hauling off the spring's dead thatch and the autumn's oak leaves — it adds up to a place that reads as cared for from the road. There is a plain pleasure in the last pass of the mower: the machine off, the lawn suddenly quiet and even. Lawn care in Billerica and the towns nearby, one yard at a time.