Dew still sits heavy when the first mower starts, and the fog is only just letting go of the Mississippi. Thompson Acres Quad Cities cuts lawns across South Moline, where the cottonwoods along Ben Butterworth Parkway send their cotton drifting through June and the yards run flat and green almost to the bank. Mowing, trimming, edging, seasonal cleanups — the work is simple to name and hard to do right, and the proof of it is the straight seam where turf meets sidewalk. By afternoon the striping reads plain from the street, light and dark, laid the long way down the lot. That is a good thing to leave behind on a river-town block.