Breen_2024

2/14/24, 6:23 PM
College of Agricultural Sciences - Department of Horticulture »
Landscape Plants
Thuja
occidentalis
Common name: Eastern Arborvitae
American Arborvitae
Eastern White-cedar
Pronunciation: THEW-ya ok-si-den-TA-lis
Family: Cupressaceae
Genus: Thuja
Type: Conifer
Native to (or naturalized in) Oregon: No
> 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 'Teeny' 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).
https://landscapeplants.oregonstate.edu/plants/thuja-occidentalis

Click image to enlarge
in habitat, Maine
plant habit
plant habit, hedge
plant habit, tall screen
https://landscapeplants.oregonstate.edu/plants/thuja-occidentalis

leaves and cones
mature cones and leaves
Tfngw p c l v j i v .vim j
leaves (underside), comparison
leaves, comparison
trunk, bark
Genus Thuja
> Eastern Arborvitae
Thuja occidentalis
> American Arborvitae
) Eastern White-cedar
Thuja occidentalis 'Golden Globe'
Thuja occidentalis 'Hetz Midget'
Thuja occidentalis 'Rheingold'
Thuja occidentalis 'Yellow Ribbon'
) Golden Globe Arborvitae
> Hetz Midget Arborvitae
) Rheingold Arborvitae
) Yellow Ribbon Arborvitae
https://landscapeplants.oregonstate.edu/plants/thuja-occidentalis

Thuja orientalis
> Chinese Arborvitae
> Oriental Arborvitae
Thuja plicata
) Western Red Cedar
> Giant Western Arborvitae
Thuja plicata 'Atrovirens'
) Atrovirens Western Red Cedar
) Atrovirens Giant Western Arborvitae
Thuja plicata 'Can Can'
i Can Can Western Red Cedar
) Can Can Giant Arborvitae
Thuja plicata 'Grune Kugel'
) Grune Kugel Cedar
> Grune Kugel Western Red Cedar
Thuja plicata 'Stoneham Gold'
) Stoneham Gold Cedar
) Stoneham Gold Western Red Cedar
Thuja plicata 'Zebrina'
) Zebrina Cedar
) Zebrina Western Red Cedar
Contact Info
Patrick Breen,
CPN (Certified Plant Nerd)
Patrick.Breen@oregonstate.edu
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https://landscapeplants.oregonstate.edu/plants/thuja-occidentalis