The Raritan takes its slow bend just south of town, and in July the air off it sits heavy over Somerville by mid-morning. Garden Lawn Maintenance LLC starts early for that reason — mowing while the dew is still down and the heat hasn't stacked up yet. Grass cut at the right height in that humidity holds its color through the worst weeks of summer. Trimming, edging, cleanups when the season turns: the list is short and the standard isn't. By the time the cicadas start up in the afternoon, the route is done and the yards show it.