Dark Green Arborvitae, Nigra Arborvitae, Thuja Occidentalis 'Nigra', is commonly called Dark Green Arborvitae. Nigra Arborvitae or Dark Green Arborvitae is a beautiful pyramidal growing tree that makes excellent privacy hedges. As with most arborvitaes, the Nigra or Dark Green Arborvitae is a moderate grower. The dark green foliage is consistent and when planted for privacy hedge makes an appealing backdrop to more colorful shrubs and perennials. Typical mature width of the Nigra Arborvitae or Dark Green Arborvitae is 10 feet with a mature height of in the 20 to 30 feet tall range. Many arborvitaes are attractive to deer, so if you have a deer problem in your area, be protective with this plant variety.