Arborvitae are not true cedars, despite being sold under names like “Eastern White Cedar” and “Western Red Cedar” at nearly every garden center in North America. The trees most people call cedars in the United States and Canada belong to the genus Thuja, which sits in the cypress family. True cedars belong to a completely different genus, Cedrus, in the pine family, and they grow wild only in the Mediterranean and the western Himalayas. The confusion runs centuries deep, tangled up in colonial-era botany, Indigenous woodworking traditions, and the lumber trade, and it affects everything from how you care for the trees to what you can expect from their wood.
How Two Unrelated Trees Ended Up Sharing a Name
When French explorers arrived in eastern Canada in the 1500s, they encountered Thuja occidentalis and noticed that its fragrant, rot-resistant wood reminded them of the cedars described in biblical and classical texts. They called it “arborvitae,” Latin for “tree of life,” reportedly because a tea brewed from its foliage helped cure scurvy during Jacques Cartier’s expedition. At the same time, English-speaking settlers on the Pacific coast found Thuja plicata, an enormous conifer whose wood split cleanly into planks and resisted decay for decades. They called it “cedar” because its aromatic, durable heartwood was the closest thing they knew to the famed Cedar of Lebanon. The name stuck, and by the time formal botanical classification caught up, “cedar” had become embedded in the common vocabulary for these trees across an entire continent.
True cedars, the species in the genus Cedrus, were already well known in Europe and the Middle East. The Cedar of Lebanon (Cedrus libani) appears throughout ancient texts, prized for temple construction. The Atlas Cedar (Cedrus atlantica) grows in North Africa, and the Deodar Cedar (Cedrus deodara) is native to the western Himalayas. These are the only trees that botanists consider genuine cedars. They look and behave differently from arborvitae in almost every measurable way.
The Family Tree Split
The separation between arborvitae and true cedars is not a minor taxonomic quibble. It runs all the way up to the family level. Arborvitae belong to the family Cupressaceae, the cypress family, which also includes junipers, bald cypress, and redwoods. True cedars belong to Pinaceae, the pine family, alongside pines, spruces, firs, and hemlocks. These two families diverged deep in evolutionary history. Research using fossil calibration and molecular dating has shown that the Cupressaceae family originated during the Triassic period, when the supercontinent Pangea was still intact, with key subfamily splits occurring around 150 million years ago as landmasses separated.1PubMed Central. Distribution of living Cupressaceae reflects the breakup of Pangea That means calling an arborvitae a cedar is roughly as accurate as calling a dog a cat because both have fur. The two lineages have been on separate evolutionary paths for an extraordinarily long time.
How to Tell Them Apart in Person
Once you know what to look for, distinguishing an arborvitae from a true cedar is straightforward, even from a distance. The differences show up in their leaves, cones, growth habit, and overall stature.
- Leaves: Arborvitae have flat, scale-like leaves arranged in overlapping sprays that feel soft when you run your hand along a branch. True cedars have clusters of stiff, needle-like leaves that radiate outward from short woody shoots, more like a larch or pine in feel.
- Cones: Arborvitae produce small, elongated cones about a centimeter long that look like tiny rosettes and open to release winged seeds. True cedar cones are barrel-shaped, upright, and much larger, sometimes reaching 12 centimeters. They sit on top of branches like ornaments and disintegrate on the tree rather than falling whole.
- Branching pattern: Arborvitae branches tend to be flat and fan-shaped, creating a dense, layered canopy. True cedars develop wide-spreading, horizontal limbs that give the tree an open, layered silhouette, especially as it matures.
- Size and shape: The most common arborvitae in landscaping, Thuja occidentalis, is a medium-sized tree that rarely exceeds 15 meters in cultivation and often stays much smaller in its popular hedge cultivars. Thuja plicata, the Western Red Cedar, is the giant of the group, reaching over 60 meters in old-growth forests. True cedars are large, spreading trees but tend to grow wider relative to their height, with the Deodar Cedar in particular developing a graceful, weeping crown.
- Bark: Arborvitae bark is thin, fibrous, and peels in vertical strips. True cedar bark is thicker, more deeply furrowed, and breaks into blocky or scaly plates.
These differences reflect the deep evolutionary divergence between the two groups. They are not subtle variations within a closely related group of conifers. They are the kind of structural differences you would expect from lineages that parted ways before the dinosaurs went extinct.
The Chemistry Inside Arborvitae
Arborvitae have a distinctive chemical profile dominated by thujone, a compound that gives the foliage its characteristic sharp, camphor-like scent. Studies of Thuja plicata have found that the essential oils from leaves and twigs contain roughly 52 to 59 percent alpha-thujone, with fenchone and beyerene as secondary components. Cultivated varieties can contain even more, with some cultivars reaching over 76 percent thujone in their twig oils.2Natural Product Communications. Chemical Composition of the Essential Oils From Twigs, Leaves, and Cones of Thuja plicata and Its Cultivar Varieties “Fastigiata”, “Kornik,” and “Zebrina” This compound is the source of the genus name itself: Thuja derives from an ancient Greek word for a type of aromatic tree.
Thujone is also the reason arborvitae have a long history in folk medicine and why they should be handled with some respect. Thuja occidentalis has been reviewed for its antiviral activity and its effects on the immune system, including stimulation of cytokine production and activation of immune cells.3Evidence-based Complementary and Alternative Medicine. Thuja occidentalis (Arbor vitae): A Review of its Pharmaceutical, Pharmacological and Clinical Properties However, thujone in concentrated form is toxic, which is why arborvitae essential oil should never be ingested. The same compound that makes the wood resistant to insects and fungal decay makes the plant pharmacologically active in ways that can be dangerous without proper formulation.
True cedars contain a different suite of aromatic compounds. Cedarwood oil from Cedrus species is rich in sesquiterpenes like himachalol and atlantone rather than thujone. The scent profiles overlap just enough to seem related, which probably reinforced the “cedar” misnomer when settlers first encountered arborvitae, but the underlying chemistry is distinct.
Why Indigenous Peoples Built Civilizations Around “Cedar”
The Western Red Cedar, Thuja plicata, was arguably the single most important plant resource for Indigenous cultures along the Pacific Northwest coast. Paleobotanical records show a strong correlation between the expansion of Thuja plicata in coastal forests between 5,000 and 2,500 years ago and the development of massive woodworking technology by native cultures. Researchers have argued that the cultural evolution of canoe-building and plank-house construction was environmentally constrained until large cedar trees became available during the late Holocene.4Science. Holocene history of cedar and native Indian cultures of the north american pacific coast
The wood of Thuja plicata is light, straight-grained, and splits evenly along its length, making it ideal for hand-worked construction without metal tools. Its natural resistance to moisture and decay meant that dugout canoes, longhouses, and totem poles could last for generations. Bark was stripped and woven into clothing, baskets, and rope. The tree’s cultural significance earned it names in several Indigenous languages that translate roughly to “tree of life,” the same meaning the French gave to Thuja occidentalis on the opposite side of the continent, independently and for different reasons.
True cedars, meanwhile, played their own role in ancient Mediterranean and Near Eastern civilizations. The Cedar of Lebanon was so central to Phoenician shipbuilding and Egyptian coffin construction that overharvesting depleted its range thousands of years ago. Both groups of trees earned outsized cultural importance because of the same practical quality: rot-resistant, aromatic heartwood. That functional similarity, more than any botanical kinship, is why the shared common name persists.
Arborvitae and Wildlife
In the northeastern United States and eastern Canada, Thuja occidentalis plays an ecological role that true cedars do not and could not fill. Northern White Cedar stands serve as critical winter habitat for white-tailed deer. The dense, low-branching growth of arborvitae creates thermal cover that reduces wind chill and snow depth on the forest floor, and deer browse the foliage heavily as a winter food source. Research has noted that some individual trees are preferentially browsed while nearby trees are left untouched, suggesting chemical variation between individuals that affects palatability.5Michigan Technological University. Identifying chemical compounds responsible for white-tailed deer (Odocoileus virginianus Zimmerman) browse resistance in northern white-cedar (Thuja occidentalis L.)
This browsing pressure is so intense in some regions that it has become a conservation concern. Dense deer populations can strip the lower branches of arborvitae stands, creating a visible “browse line” and preventing regeneration of young trees. The relationship between deer and arborvitae is an ecological feedback loop: the trees create the habitat that concentrates the deer, and the concentrated deer then damage the trees. Land managers in the Great Lakes region and New England grapple with this cycle constantly. True cedars, being native to entirely different ecosystems, have no equivalent relationship with North American wildlife.
What the Name Confusion Means for Your Yard
If you are shopping for trees or hedging, the arborvitae-cedar mix-up can lead to real misunderstandings. Here are the practical differences that matter most when you are standing in a nursery aisle.
Arborvitae, particularly the dozens of cultivars of Thuja occidentalis and Thuja plicata, are among the most popular privacy hedges in North America. They grow in a tight columnar or pyramidal shape, tolerate cold climates well (many are hardy into USDA Zone 3), and respond to shearing. The trade-off is that they are shallow-rooted, prone to winter burn in exposed sites, and can be devastated by deer browsing and bagworm infestations. Their scale-like foliage turns bronze in winter in some varieties, which surprises people who expected year-round green.
True cedars, when they are available in the nursery trade, are ornamental specimens rather than hedge material. The Deodar Cedar is the most commonly planted in North America, valued for its graceful, pendulous branching and blue-green needles. It is far less cold-hardy than arborvitae, generally limited to USDA Zone 7 and warmer. The Atlas Cedar is similarly zone-restricted. Neither is used for screening or hedging because their natural form is wide and open rather than dense and columnar. If someone tells you they planted “a cedar hedge,” they are almost certainly talking about arborvitae, not Cedrus.
The wood products carry the same naming confusion. “Cedar” lumber sold at home improvement stores for decking, fencing, and siding is overwhelmingly Thuja plicata (Western Red Cedar) or Juniperus virginiana (Eastern Red Cedar, which is actually a juniper and yet a third case of mislabeling). True cedar wood from Cedrus species is rarely available commercially in North America. If you are buying cedar for a project, you are buying arborvitae wood or juniper wood, and there is nothing wrong with that. It performs exactly as advertised for outdoor use. You are just not buying what a botanist would call cedar.
Other “Cedars” That Aren’t Cedars Either
Arborvitae are far from the only trees trading on the cedar name without botanical justification. The list of imposters is long enough to be comical.
- Eastern Red Cedar: Juniperus virginiana, a juniper. Common across the eastern United States, it is the tree whose wood lines closets and cigar boxes. It belongs to the same cypress family as arborvitae but is not closely related to either Thuja or Cedrus.
- Incense Cedar: Calocedrus decurrens, also in the cypress family. Native to the western United States, it is the primary wood used to make pencils. Not a cedar.
- Japanese Cedar: Cryptomeria japonica, another cypress family member. A towering conifer planted widely as a timber tree in Japan and an ornamental elsewhere. The genus name means “hidden parts,” a reference to its concealed reproductive structures, not to any hidden cedar identity.
- Alaska Yellow Cedar: Callitropsis nootkatensis (recently reclassified from Chamaecyparis), yet another cypress relative. Valued for boat-building and totem poles, it grows in coastal forests from Alaska to Oregon.
- Port Orford Cedar: Chamaecyparis lawsoniana, a cypress-family tree from a tiny range in southwestern Oregon and northwestern California. It has been ravaged by a root disease since the mid-twentieth century and is now a significant conservation concern.
Every one of these sits in Cupressaceae. The pattern is consistent: any conifer with fragrant, rot-resistant wood and a vaguely “cedary” smell got called a cedar by English-speaking settlers, regardless of its actual relationships. The only true cedars in the strict botanical sense remain the three or four species (depending on which taxonomist you ask) in the genus Cedrus. Some authorities count Cedrus brevifolia, the Cypriot Cedar, as a fourth species, while others consider it a subspecies of the Cedar of Lebanon. Either way, none of them grow wild in the Americas.
Why the Misnaming Persists
Botanists settled the arborvitae-versus-cedar question a long time ago, and yet the common names have not budged. Part of the reason is sheer inertia. The lumber industry labels Western Red Cedar as cedar, building codes reference cedar by its trade name, and nurseries stock “Emerald Green Cedar” without a footnote. Changing a common name after centuries of use would mean rewriting product labels, construction standards, and field guides. Nobody with authority over those documents has enough motivation to do it.
There is also a genuine argument that common names do not need to match scientific taxonomy. Common names serve communication, not classification. When a homeowner asks for “a cedar hedge,” both the homeowner and the nursery worker know exactly what is meant. The word “cedar” in everyday English refers to a category of aromatic, rot-resistant softwoods, and arborvitae fit that functional definition even if they fail the genealogical one. Insisting on strict nomenclature in casual conversation would be like correcting someone who calls a tomato a vegetable. You would be right, and nobody would thank you for it.
Where the distinction genuinely matters is in horticulture and ecology. Planting advice for Thuja occidentalis is completely irrelevant to Cedrus deodara, and vice versa. Their hardiness zones barely overlap, their water needs differ, their pest profiles have nothing in common, and their growth habits could not be more different. If you are reading care instructions online, make sure the article is actually about your tree. The easiest check is to look for the Latin name: Thuja means arborvitae, Cedrus means true cedar, and Juniperus means you have wandered into juniper territory. Getting this right saves you from applying the wrong pruning schedule, the wrong soil amendment, or the wrong pest treatment to a tree that does not need it.