The tall, narrow, dark green evergreens often used for screening or accents are commonly called “cedars.” This is a widespread misnomer, as these popular columnar evergreens belong to different genera than true cedars. The confusion persists because many trees in the cypress family are colloquially given the “cedar” name.
Solving the Identity Crisis
Most trees recognized as “tall skinny cedars” fall into two primary categories based on climate and specific form. The most common is the columnar Arborvitae, belonging to the genus Thuja, particularly cultivars of the species Thuja occidentalis. The cultivar ‘Emerald Green’ (‘Smaragd’) is widely planted for its dense, bright green foliage and naturally narrow, pyramidal shape. This Arborvitae typically matures to a manageable height of 10 to 15 feet with a spread of only 3 to 4 feet, making it ideal for tight spaces and privacy hedges.
In warmer regions, the striking, pencil-thin evergreen is likely the Italian Cypress (Cupressus sempervirens). This tree is notable for its extremely fastigiate, or upright and parallel-branched, form, which creates a powerful vertical line in the landscape. The Italian Cypress can reach heights of 30 to 40 feet while remaining only a few feet wide. Arborvitae and Italian Cypress are the two most frequently encountered columnar lookalikes.
Distinguishing True Cedars from the Lookalikes
The common name “cedar” is misleading due to the plants’ taxonomy. True Cedars (Cedrus) are part of the Pine family (Pinaceae). The lookalikes, such as Arborvitae (Thuja) and Cypress (Cupressus), belong to the Cypress family (Cupressaceae). This difference in family translates directly to visual distinctions in the foliage.
True cedars have short, stiff needles clustered in dense rosettes. They naturally develop a wide, spreading, pyramidal canopy when mature, unlike the narrow lookalikes. Arborvitae and Cypress foliage consists of tiny, overlapping, scale-like leaves that form flat, lacy sprays. The misnomer persists because many Cupressaceae species, such as the Eastern Red Cedar (Juniperus virginiana), were historically named “cedar” despite being Junipers.
Key Considerations for Planting and Placement
These narrow evergreens are primarily selected for architectural purposes, serving as formal accents or fast-growing privacy screens. When planting for a dense hedge, the spacing is a factor for the long-term health of the trees. A common error is planting the trees too close together in an attempt to achieve immediate privacy.
For Arborvitae cultivars like ‘Emerald Green’, planting them too tightly, such as less than three feet apart, can severely restrict air circulation. Poor air flow causes the dense foliage to remain damp, which increases the risk of fungal disease, browning, and pest infestations. It is recommended to space them four to five feet apart center-to-center, allowing the trees to grow together naturally.
Both Arborvitae and Cypress require well-drained soil and prefer at least six hours of direct sunlight daily to maintain their dense, uniform shape. They do not tolerate constantly wet conditions, which can quickly lead to root rot and tree decline. While the Italian Cypress is known for its drought tolerance once established, Arborvitae needs consistent moisture, especially during its first few years and during periods of extreme heat.
To maintain the desired narrow profile, occasional light shearing is necessary to keep the foliage thick and neat. Care must be taken not to cut back into the old, leafless wood, as this wood will not regenerate new growth and will leave permanent brown patches. Homeowners should also be aware that the foliage of some Arborvitae varieties is susceptible to winter burn and grazing damage from deer.