Lake Williams sits quiet behind its screen of trees on the west side of Marlborough, and the streets that climb away from it hold small yards stacked one above the next like steps. Somar Landscape mows that neighborhood in May, when everything is growing at full tilt and a lawn can get away from a person in six days flat. The work is unfussy and exact: even cuts, trimmed fence lines and walls, mulch renewed dark in the beds, clippings taken away rather than left to sit. A tight yard is harder than a big one — every edge is visible from the porch, so every edge has to be right. Come autumn the same properties get cleared down to bare grass and set up for the cold.