a.k.a. American arborvitae is an ornamental and timber evergreen conifer of the cypress family. Its shimmering emerald green year-round dense foliage makes the best hedge or privacy screen. They will grow to a mature height of 15 to 25 feet and a mature spread of 4 to 6 feet. They prefer full sun to partial shade, and can grow in a variety of soil conditions. This is one of the most cold-hardy trees known.