The name “Red Cedar” is used for different species of evergreen trees, which can cause confusion regarding growth rates. This article focuses primarily on the Eastern Red Cedar (Juniperus virginiana), the most widespread and commonly planted species in the eastern United States. It is important to note that this tree is not a true cedar, but a member of the juniper family, known for its dense, aromatic wood. The growth rate is highly dependent on the specific environment and care the tree receives.
The Standard Annual Growth Rate
The Eastern Red Cedar is typically classified as having a moderate growth rate, averaging a vertical increase of 1 to 2 feet per year under optimal conditions. This measurement represents the tree’s performance once it has established a root system. Seedlings and newly transplanted trees often exhibit slower growth in their first few years as they dedicate energy to establishing roots rather than vertical height.
The peak growth years occur after this juvenile stage, where the tree can consistently add close to two feet annually, particularly when provided with ample resources. This contrasts with the Western Red Cedar (Thuja plicata), a species native to the Pacific Northwest, which is significantly faster growing. The Western Red Cedar often achieves a rate of 2 to 3 feet per year. The Eastern Red Cedar’s moderate rate allows it to adapt to a wide range of poor soils and harsh conditions across its native range.
Environmental Factors That Affect Growth Speed
The actual speed at which an Eastern Red Cedar grows is heavily influenced by the conditions of its planting site. Sunlight is one of the most significant factors, as this species is highly sun-adapted, with full sun exposure leading to the fastest growth. Trees planted in heavy shade will experience a considerable slowdown in growth, sometimes resulting in a more shrub-like, less vertical form.
Soil quality and drainage also play a major role in optimizing the growth rate. While the Eastern Red Cedar is famously tolerant of poor, dry, and rocky soils, it will grow much faster in deep, well-drained loamy soil with a neutral to slightly alkaline pH. The species is highly intolerant of standing water, and growth will be severely stunted or stopped entirely in constantly wet or swampy areas.
Although the tree is highly drought-tolerant once established, consistent, moderate water availability during the initial establishment period significantly boosts its growth speed. During dry seasons, supplemental irrigation can prevent the growth rate from slowing down. Regional climate also imposes limits; growth is negatively correlated with high summer temperatures and can slow in areas with extreme cold or high altitude.
Long-Term Trajectory and Mature Dimensions
The period of its fastest growth, adding 1 to 2 feet annually, typically lasts for the first 10 to 15 years of the Eastern Red Cedar’s life. After this initial phase, the tree begins to shift its energy from rapid vertical expansion toward increasing its density and girth. This transition marks the tree’s progression toward semi-maturity, where the annual height increase slows.
The mature dimensions of an Eastern Red Cedar typically fall between 40 and 50 feet in height, with a spread of 8 to 20 feet, often exhibiting a dense, pyramidal shape. On exceptional sites, some specimens can exceed 60 feet in height and live for hundreds of years. The tree reaches a functional semi-maturity, providing significant screening and windbreak benefits, within 20 to 30 years.