Thuja plicata

Giant Arborvitae, Western Arborvitae




  • native to west coast of North America
  • hardy to zone 5, and warmer parts of 4

Habit and Form

  • an evergreen tree
  • pyramidal shape
  • 50' to 70' tall
  • up to 25' wide
  • foliage to ground
  • medium texture
  • moderate growth rate

Summer Foliage

  • long-pointed scale like new leaves
  • resin gland on scales
  • older leaves are blunt with no gland and overlapping
  • glossy dark green
  • crushed foliage emits a distinct tansy-like odor

Autumn Foliage

  • foliage discolors to yellowish-green and even somewhat brown at times
  • winter color is considered ugly by sone and cultivars have been selected for green winter foliage color


  • not of any ornamental significance
  • monoecious
  • at the branch tips
  • borne singly


  • small erect cones with thin, overlapping scales
  • ovoid
  • green maturing to brown to tan
  • 0.5" long
  • not particularly noticeable except when then is heavy cone set
  • winged seeds


  • reddish-brown stems
  • grayish older bark
  • fibrous
  • furrowed into relatively narrow strips
  • reasonably ornamental when visible on older specimens


  • easily transplanted from containers and B&B
  • likes moist air
  • prefers moist, deep, loamy soil
  • tolerant of acidic and alkaline soils
  • generally quite adaptable and tolerant once established
  • can be sheared to maintain shape and size
  • full sun; partial shade is tolerated but plants become thin, open and much less appealing
  • tolerant of somewhat wet soils

Landscape Uses

  • for hedges
  • for screens
  • windbreaks
  • specimen
  • foundation plant (small cultivar)
  • cultivar selected for green winter foliage should be used in place of species


  • leaf miner
  • bag worms
  • foliar burn in very harsh sites
  • spider mites
  • heavy snow often causes damage
  • a favorite food of deer

ID Features

  • fern-like branches
  • conical shape
  • dense, compact evergreen foliage
  • scale-like leaves
  • tansy-like odor emitted from crushed foliage
  • small woody cone
  • buttressed base


  • by seed
  • cultivars by cuttings


'Canadian Gold' (very similar to 'Sunshine') - This pyramidal grower bears golden foliage that holds all year. In time, the plant may reach 70' tall with a spread of only 20'.

'Cuprea' - This dwarf form holds a globular shape to 4' tall and wider. The newest growth is tinged yellow, turning bronzy in winter.

'Green Giant' (probably the same as 'Spring Grove', both of which are most likely hybrids of Thuja standishii and T. plicata) - This plant has been heavily promoted by catalogs seeking to quench the thirst many gardeners have for fast-growing evergreen plants. This plant does indeed exhibit excellent vigor and habit, reaching 50' tall with a spread of 10'. It is a dense, conical plant clothed in dark green foliage. Though promoted as having foliage that remains verdant in winter, observations have revealed bronzing. In addition, the purported deer resistance has not proved completely reliable. Nevertheless, the plant can grow more than 3' each year under optimal conditions.

'Green Sport' (probably the same as 'Watnong Green', similar to 'Virescens') - This plant bears healthy green foliage that appears to hold its color well in winter. Other traits are as per the species.

'Pumila' - The habit of this plant is like the species, but is very slow-growing and forms a dense, dwarf pyramid.

'Whipcord' - Unusual both for its dwarf, shrubby form and foliage that is arranged on stringy, pendulous branchlets, this selection will reach about 5' tall and wide after many years. The foliage is green in summer and bronzes in winter.

'Zebrina' - A catch-all name for a number of clones, most plants form a broad pyramid that in time may grow 60' tall. The most notable feature, however, is the variable yellow striping on the sprays of foliage. From a distance, the plant assumes a yellow-green cast. 'Zebrina Extra Gold' has even more accentuated yellow coloring on a slower-growing plant. The strong highlights will probably fade in warm summer areas.

© Copyright Mark H. Brand, 1997-2015.

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Citation and Acknowledgements: University of Connecticut Plant Database,, Mark H. Brand, Department of Plant Science and Landscape Architecture, Storrs, CT 06269-4067 USA.