Down by Derby Wharf in May the harbor turns a particular blue, the masts stand up against it, and every scrap of green in the old town reads twice as green for being ringed in brick and cobble. Salem Design Landscape & Construction works the lawns and grounds of a city where the yards are small and the standards are old: mowing and trimming on a set rhythm, edging along walks and granite, mulch and bed shaping, planting, sod and seeding, and cleanups in spring and autumn. A tight courtyard lawn cut square and edged close can hold its own against anything on the hill. Wind off the water dries a new seeding out fast, so timing and watering are half the craft. By June the beds have filled, the turf has knit, and the place looks as though it was always that way.