Thuja Occidentalis

By Davis Landscape Architecture @DavisLandArch

Thuja occidentalis (30/12/14, Kew Gardens, London)

Position: Full sun

Flowering period: Spring

Soil: Moist, well drained

Eventual Height: 20m

Eventual Spread: 5m

Hardiness: 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b

Family: Cupressaceae

Thuja occidentalis is an evergreen coniferous tree with a variable habit. Its mid green leaves are  scale like, up to 5mm long, forms flat sprays, are borne on growing lead shoots and smell of pineapple when crushed. Its trunk may achieve a diameter of up to 40cm. Its red/ brown bark is smooth with furrows and peels in longitudinal strips. Its leaves may become bronzed during the winter months. Its monoecious flowers appear as pollen cones and cones. Its fruit are cones, up to 15mm long, 5mm broad and initially green/ yellow become brown autumn.

Thuja occidentalis Leaf (30/12/14, Kew Gardens, London)

The species Thuja occidentalis, commonly known as White Cedar, Atlantic White Cedar or Arborvitae, is native to the north east United States and south east of Canada. In its native habitat it grows in wet forests and other locations where completion from other trees is low.

The etymological root of the binomial name Thuja is derived from the Greek thuo meaning ‘to sacrifice’, in reference to the wood being burned with animal sacrifices by the ancient Greek to add a pleasing aroma to the fire. Occidentalis is from the Latin meaning ‘from the west’.

The landscape architect may find Thuja occidentalis useful as a screening hedging species.

Ecologically, Thuja occidentalis is of little wildlife value in the UK.

Thuja occidentalis Bark (30/12/14, Kew Gardens, London)

The Royal Horticultural Society has given various cultivars of Thuja occidentalis their prestigious Award of Garden Merit.

Thuja occidentalis prefers moist, fertile, well-drained soils. It tolerates most pH of soil. It dislikes dry soils.

Thuja occidentalis requires little maintenance. If being maintained as a hedge it should be trimmed once a year in early August.