emerald arborvitae - A good plant for a wall of green with minimal maintenence is Emerald Green arborvitae. Just needs a trimming once a year to keep it at the height you want, and in the spring, just tye up and branches that the snow bent. I used it in Watertown, and again in Lexington.
The Emerald Green Arborvitae, Thuja occidentalis 'Smaragd', also known as Emerald Green Thuja is a fast-growing, hardy arborvitae. It would make a superb privacy hedge along your property line or beside your backyard pool. These also make an excellent wind-break or foundation plant.