Arborvitae are evergreen conifers, primarily belonging to the genus Thuja, widely used in landscaping. The common name, meaning “tree of life,” hints at the plant’s historical medicinal value. These trees and shrubs are popular choices for hedges and privacy screens due to their dense growth habit and year-round green color. Examining the foliage, structure, and bark reveals the specific characteristics that define the Arborvitae’s appearance.
The Signature Foliage and Coloration
The most distinguishing feature of the Arborvitae is its unique foliage, composed of tiny, scale-like leaves. Unlike the sharp, pointed needles of pines or spruces, these leaves are soft to the touch and lie flat against the stems. The small, overlapping scales are tightly pressed together, forming flattened, fan-like sprays that give the plant a fine, lacy texture.
The coloration typically ranges from vibrant emerald green to deep forest green, depending on the specific cultivar. Some varieties, like ‘Smaragd’ or ‘Emerald Green’, are bred to maintain this rich color year-round. Other cultivars feature striking golden-yellow foliage when grown in full sun.
A common visual characteristic, particularly in the Eastern Arborvitae (Thuja occidentalis), is “bronzing” or browning in the winter. As temperatures drop, the green pigment fades, causing the foliage to take on a chartreuse-brown or coppery hue. Crushing the foliage releases a distinct, often sweet or citrus-like fragrance, which is a key identification marker.
Diverse Growth Habits and Mature Size
The overall shape, or growth habit, of an Arborvitae is highly variable, ranging from compact, rounded shrubs to towering, narrowly conical trees. The density of the branches makes many varieties excellent for creating a solid, year-round privacy barrier. The silhouette can be broadly pyramidal, like the fast-growing ‘Green Giant,’ or take on a slender, columnar form, such as ‘Emerald Green.’
The mature size is heavily dependent on the cultivar. Some dwarf varieties, like ‘Hetz Midget’ or ‘Tater Tot,’ maintain a globe shape and reach only two to three feet in height and width. Conversely, larger selections, such as the Thuja plicata species, can grow to heights of 50 to 60 feet or more in a landscape setting.
The branching structure is generally dense and upright, contributing to its reputation as a sturdy screening plant. However, the wood is relatively lightweight and prone to bending or breakage under the weight of heavy, wet snow or ice. This potential for damage is more noticeable in the taller, narrower varieties.
Secondary Identification Marks
The trunk and bark of mature Arborvitae offer additional identification clues, though they are often hidden by the dense foliage. The bark is typically thin, reddish-brown or grayish-brown, and has a fibrous or stringy texture. On older trees, the bark often peels or shreds vertically in long, narrow strips.
Reproductive structures are small and generally inconspicuous, appearing as tiny cones. The female cones are woody and oblong, usually measuring around half an inch long, and are often described as looking like miniature dried rosebuds. These cones are borne near the tips of the branches and may persist on the tree through the winter.
The male cones are even smaller and are typically rounded, appearing reddish or yellowish before they mature. The wood is soft, light in weight, and durable, which is why it has historically been used for fence posts and other outdoor applications.