Thuja plicta commonly known as Green Giant Arborvitae is appropriate for Zone 5-8. This tree is a large, vigorous, fast-growing evergreen—shooting up by as much as 3 feet per year until maturity. Its natural pyramidal to conical form boasts dense, rich green foliage that darkens or bronzes slightly in the winter. Height 40-60ft. Spread 12-18ft.