Thuja plicata 'Atrovirens'

A Victorian-era English selection of one of the great trees of North America. The species (Thuja plicata, 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 1,000 years old. To the Coast Salish, Haida, Tlingit, Kwakwaka'wakw, and other Pacific Northwest Indigenous peoples, it 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 ceremonial dress; the entire tree the structural and cultural foundation of an entire civilization for thousands of years. The wood's natural rot-resistance comes from the same volatile terpenoid compounds that give the foliage its characteristic sweet-cedary fragrance when crushed, a fragrance that is the smell of the Pacific Northwest forest itself.

'Atrovirens' is the form most American gardeners will encounter. It originated as a selected seedling at a nursery in Worcester, England, around 1874, Victorian-era horticulture making a refined cultivar from an Indigenous American giant. The Latin name combines atro (dark) and virens (green) to mean precisely what it describes: a dark-green form, glossier and richer than the typical Pacific Northwest population, with denser foliage and a more uniformly conical habit. It received the Royal Horticultural Society's Award of Garden Merit in 2002, meaningful horticultural recognition that this is a reliably good clone, not just a good species. In garden cultivation, 'Atrovirens' reaches 25 to 45 feet tall and 8 to 15 feet wide, a fraction of its wild parent's stature, but more than enough for practical garden use as a specimen, screen, hedge, or windbreak.

What makes this tree useful in the Southeast and East, well outside its Pacific Northwest home range, is a combination of three things. First, it tolerates eastern conditions remarkably well when properly sited (deep moist well-drained soil, full sun to part shade, protection from drying winter winds). Second, it is substantially deer-resistant, a meaningful advantage over the East's standard hedging conifer, Thuja occidentalis (American arborvitae), which deer will browse to skeletons in any landscape with deer pressure. Western red cedar's terpenoid chemistry is significantly less palatable to white-tailed deer. Third, it takes hard pruning without complaint: cutting back into old wood does not produce the dead brown patches that can plague other hedging conifers, which means a dense formal hedge can be maintained at any height the 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, with that characteristic aromatic resin released when crushed. Glossy dark green through summer; in cold weather the foliage may pick up bronze or coppery tinges that some gardeners find appealing and others find awkward (it greens back up in spring). The foliage texture, viewed up close, is genuinely lovely, fine and lacy and refined, much more so than the cruder texture of common Leyland cypress or Italian cypress.

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