On Round Hill in May the wind off the water gets into everything, and the grass grows so fast you can nearly hear it. Lavoie Landscaping spends that season chasing it — mowing, trimming, cutting the bed edges back into shape after a winter of blown sand and broken twigs. By August the pace changes and the work becomes upkeep: even height, squared corners, a lawn that looks the way its owner pictured it. Autumn is the long haul of leaves, moved off the turf before wet weather mats them down. Dartmouth rewards patience, and a well-kept yard here is a small argument in its favor.