On a July evening the light coming off Lake Attitash turns low and gold, and every lawn on the Merrimac side of the water picks it up for about twenty minutes before dusk. Flint Garden Designs likes to finish a day in that window: the mowing done, the bed lines freshly cut, mulch settled dark around the plantings, the whole yard reading as one composed thing rather than a list of chores. The work through the week is plain enough — mowing, trimming, keeping beds weeded and edged — but done attentively it changes how a house sits on its lot. Merrimac is a town of modest frontages and generous back yards, and there is room in nearly every one of them for something better than tidy. Seasonal cleanups bracket the year at both ends so the good months start clean.