There is an hour in June when Coggshall Park is all held breath — mist still sitting on Mirror Lake, the pines holding onto the night's cool. Boudreau Landscaping Inc is loading the trailer by then, headed out to the dooryards and back lawns on the other side of the city. The work is mowing and trimming and keeping a lawn even through a Central Massachusetts summer that can swing from downpour to drought inside a week. They cut clean lines, sweep the walk afterward, and leave a yard that plainly had someone's attention on it. That is the whole aim: grass that makes a house look glad to be lived in.