Thuja occidentalis
Common name: 
Eastern Arborvitae
American Arborvitae
Eastern White-cedar
THEW-ya ok-si-den-TA-lis
Native to (or naturalized in) Oregon: 
  • Conifer, evergreen tree/shrub, to 40 ft (12 m) high, broad pyramidal, branches erect and out spreading, densely crowded.  Bark reddish brown, fissured into narrow ridges covered with elongated scales.  Leaves in flattened branchlets, each scale-like, 2 mm long, abruptly pointed, those on the main axes conspicuously glandular, bright green above and pale green below, may become yellow-brown in winter.  Male pollen cones are small (1-2 mm), inconspicuous, at the ends of the twigs.  Seed cones when mature are 9-14 mm long and brown..
  • Sun.  Prefers a deep, well-drained soil.  When established it can withstand considerable heat and drought. Often used for hedges.   Susceptible to winter burn.  Some cultivars, such as 'Smaragd' (syn. 'Emerald' or 'Emerald Geeen'), 'Nigra', and 'Tecny' do not discolor in winter.
  • Native to USDA Zone (2)3     The species is native from eastern to central North America; from Nova Scotia west to Manitoba and south to Illinois, Tennessee and North Carolina.
  • Many cultivars:
    • Some are narrow, columnar or cone-shaped, e.g., 'Brandon', 'Degroot's Spire', 'Smaragd' i.e., 'Emerald Green', 'Nigra', and 'Pyramidalis'.  A narrow pyramidal form tends to come true from seed, but seedlings are not necessarily uniform in cultivation.
    • Some cultivars have a dwarf, compact, and/or globular habit, e.g., 'Danica', 'Globosa', 'Hetz Midget',  'Little Gem', 'Sherwood Moss', 'Tiny Tim', and 'Woodwardii'.
    • Others cultivars have golden or variegated foliage, e.g., 'George Washington', 'Gold Spot', 'Golden Globe', 'Rheingold', 'Sherwood Frost', 'Sunkist', and 'Yellow Ribbon'.
    • One has a weeping habit,  'Pendula'.
    • Another has tread-like branchlets, 'Filiformis'.
  • Occasionally used in bonsai.
  • occidentalis: the western world (as opposed to orientalis, eastern, i.e., the Orient); does not mean western North America
  • Oregon State Univ. campus: northwest Market Place West (West Hall).
Click image to enlarge
  • in habitat, Maine

    in habitat, Maine

  • plant habit

    plant habit

  • plant habit, hedge

    plant habit, hedge

  • plant habit, tall screen

    plant habit, tall screen

  • branchlets


  • leaves


  • branchlets and immature cones

    branchlets and immature cones

  • branchlets and mature cones

    branchlets and mature cones

  • leaves and cones

    leaves and cones

  • mature cones and leaves

    mature cones and leaves

  • leaves (underside), comparison

    leaves (underside), comparison

  • leaves, comparison

    leaves, comparison

  • trunk, bark

    trunk, bark