Thuja plicata 'Atrovirens'

A Victorian-era English selection of one of the great trees of North America. The species, Thuja plicata, the western red cedar, is the dominant conifer of the Pacific Northwest coastal rainforest, the tree that towers 150 to 200 feet above the forest floor in old-growth stands of British Columbia, Washington, Oregon, and northern California, with individual specimens documented at over a thousand years old. To the Coast Salish, Haida, Tlingit, Kwakwaka'wakw, and other Pacific Northwest Indigenous peoples, western red cedar is the Tree of Life: the wood used for longhouses, dugout canoes, totem poles, and ceremonial regalia; the bark woven into baskets, mats, capes, and dress; the whole tree a structural and cultural foundation for thousands of years. That natural rot-resistance comes from the same volatile terpenoids that give the crushed foliage a sweet, cedary fragrance, the smell of the Pacific Northwest forest itself.

'Atrovirens' is the form most American gardeners will meet. The clone originated as a selected seedling at a nursery in Worcester, England, around 1874, Victorian horticulture refining a garden cultivar from an Indigenous American giant. The Latin name joins atro, dark, and virens, green, and means exactly that, a dark-green form, glossier and richer than the typical Pacific Northwest population, with denser foliage and a more uniformly conical habit. The plant earned the Royal Horticultural Society's Award of Garden Merit in 2002, a meaningful sign of a reliably good clone rather than merely a good species. In garden cultivation 'Atrovirens' reaches 25 to 45 feet tall and 8 to 15 feet wide, a fraction of the wild parent's stature, but more than enough for use as a specimen, screen, hedge, or windbreak.

Three things make the tree useful in the Southeast and East, well outside the Pacific Northwest home range. First, 'Atrovirens' tolerates eastern conditions remarkably well when properly sited, in deep, moist, well-drained soil, full sun to part shade, and shelter from drying winter wind. Second, the plant is substantially deer-resistant, a real advantage over the East's standard hedging conifer, Thuja occidentalis, the American arborvitae, which deer will browse to skeletons where pressure is high; western red cedar's terpenoid chemistry is far less palatable to white-tailed deer. Third, the tree takes hard pruning without complaint, since cutting back into old wood does not leave the dead brown patches that plague other hedging conifers, so a dense formal hedge can be held at any height a gardener chooses.

The foliage is the show beyond the structure: flat sprays of small, scale-like leaves arranged in interlocking patterns on slightly drooping branchlets, releasing a sweet, resinous cedar scent when crushed. Glossy dark green through summer, the outer foliage may pick up bronze or coppery tints in cold weather, greening back up in spring. Seen up close the texture is genuinely lovely, fine and lacy and refined, far more so than the coarser Leyland cypress or Italian cypress.

A tree for the gardener planting a long-term privacy screen who wants something better than Leyland cypress, for the deer-besieged eastern landscape that has already lost a round of Thuja occidentalis, for the conifer collector drawn to Pacific Northwest natives, or for anyone who wants to plant a tree with a thousand-year cultural history behind it.