The arborvitae (Thuja) genus of shrubs and trees includes three different species comprising a large number of evergreens. Their popularity is largely due to their fast-growing, easy-to-care-for nature and the year-round visual interest they bring to a landscape. One of the more popular cultivars of the Thuja occidentalis species of arborvitae is 'Emerald Green,' which is highly prized as a hedge or screen plant, especially in colder climates. This cultivar is sometimes known as 'Smaragd,' because the plant was originally developed in Denmark (Smaragd is the Danish word for emerald).'Emerald Green' is a semi-dwarf cultivar that has a narrow pyramidal shape. The foliage consists of flat sprays of glossy bright green. The tree has urn-shaped cones about 1/2 inch long that turn reddish brown in fall. Most specimens are 7 to 15 feet in height, occasionally reaching 20 feet. It can also make a good foundation plant and is sometimes planted singly as a landscape specimen plant. Occasionally, this plant is pruned to form spiral topiaries.