American Arborvitae, White Cedar (Thuja occidentalis)
The American Arborvitae or White Cedar is a conical evergreen tree with soft dark green scales which grows to heights of 20m. All parts of the plant (especially the tips of the branches) are highly poisonous. Used as a solitary tree in large gardens or parks or as a hedge.
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Appearance
The American Arborvitae or White Cedar is a conical evergreen tree with soft dark green scales which grows to heights of 20m. All parts of the plant (especially the tips of the branches) are highly poisonous. Used as a solitary tree in large gardens or parks or as a hedge.
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Leaves
Thick scales, cymbiform and opposite on the outside, obovate and tile-like on the inside. Scales are dark green above, yellow-green below. Brownish exterior in the winter. 0.2-6cm long and 0.2-0.3cm wide.
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Leaf upperside
Thick scales, cymbiform and opposite on the outside, obovate and tile-like on the inside. Scales are dark green above, yellow-green below. Brownish exterior in the winter. 0.2-6cm long and 0.2-0.3cm wide.
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Fruits
Oblong, elliptical cones, 1-1.3cm long, initially upright, ripen in the first year, then pendent and open wide. With 8-10 scales overlapping like roof tiles, 4 of which are fertile. The winged, edged seed is slender and 3mm long.
Poisonousness
All parts of the plant, especially the wood, cones and above all the tips of the branches, contain ethereal oils comprised of monoterpenes and are therefore toxic. Consumption of toxic parts of the plant may lead to mucosal inflammations and gastrointestinal complaints with nausea, feeling of sickness, flatulence and diarrhoea.
Application
Cemeteries, gardens, solitary tree, for planting in groups, parks, evergreen hedges, forage for birds, bird protection
Native regions
North America
Location parameters
Light: sunny to off-sun; soil type: sandy-loamy to loamy; nutrient concentration: normal to high; pH value of the soil: acid to alkaline; soil: fresh to moist.
Demands
Very frost-hardy; very fume-hardy; tolerates urban climates; wind-resistant; needs well aerated soil, deep soil, no waterlogging. Light: sun to off-sun.
Growth
15 - 20m high, 3-6m in diameter
Leaves
Thick scales, cymbiform and opposite on the outside, obovate and tile-like on the inside. Scales are dark green above, yellow-green below. Brownish exterior in the winter. 0.2-6cm long and 0.2-0.3cm wide.
Flowers
Flowering period VI-VII. Pretty white blossoms with 5 petals each, 0.4-0.6cm wide. Corymbs are 5.0-10cm wide and of particular ornamental value.
Fruits
Oblong, elliptical cones, 1-1.3cm long, initially upright, ripen in the first year, then pendent and open wide. With 8-10 scales overlapping like roof tiles, 4 of which are fertile. The winged, edged seed is slender and 3mm long.
Bark
Red-brown, brown or grey-brown bark, peeling off in thin longitudinal strips or only on one side.
Roots
Surface-rooting; finely branched, some main roots go deeper.