Trees commonly called cedars are popular in many landscapes due to their towering presence and aromatic wood. Determining how long one takes to reach its full size is complex because the term “cedar” is loosely applied to a wide variety of conifers. These different species possess drastically different genetic blueprints, meaning their ultimate size and the timeline to achieve it can vary by decades or even centuries. Understanding these distinctions provides the necessary context for predicting a specific tree’s growth trajectory.
True Cedars Versus Related Species
Confusion regarding growth rates stems from the misapplication of the common name “cedar” to trees that do not belong to the genus Cedrus. Only four species, such as the Atlas cedar and the Deodar cedar, are considered “true” cedars, all native to the Mediterranean region and the Himalayas. These trees are known for their longevity and take a long time to develop their majestic, spreading form.
In North America, many popular trees share the name “cedar” despite being part of the cypress family (Cupressaceae). For instance, the aromatic Eastern Red Cedar (Juniperus virginiana) is a type of juniper, and the giant Western Red Cedar (Thuja plicata) is an arborvitae. These taxonomic differences define whether a tree grows at a moderate pace to a modest height or at a rapid pace toward becoming a long-lived giant.
Defining Maturity and Growth Stages
The concept of “full size” needs clarification because a tree’s growth does not stop suddenly. Arborists define tree development through three phases: the juvenile stage, the rapid growth phase, and the mature phase. The initial juvenile period involves establishing a strong root system, and above-ground growth may appear slow.
The rapid growth phase follows, during which the tree puts on the majority of its height and width. For many species, this rapid increase typically occurs within the first 10 to 20 years of life, assuming optimal conditions. A tree is considered reproductively mature when it begins producing cones, often before it reaches its maximum height. The final mature phase involves a significant slowing of vertical growth as the tree focuses energy on thickening its trunk, developing its canopy, and maintaining overall health.
Average Annual Growth Rates
The quantifiable growth rate for a cedar-named tree depends entirely on its species classification. Trees labeled as fast-growing are typically the North American false cedars, which can quickly establish a privacy screen or windbreak. For example, the Western Red Cedar exhibits a rapid growth rate, adding between two and three feet of height per year under ideal conditions. The Eastern Red Cedar commonly gains one to two feet annually.
True cedars, such as the Atlas cedar (Cedrus atlantica) and Deodar cedar (Cedrus deodara), generally exhibit a moderate growth rate, averaging between one and two feet of vertical growth per year. The Cedar of Lebanon (Cedrus libani) is a slower grower, sometimes adding less than one foot annually. Consequently, a fast-growing variety could reach 50 feet in under 20 years, while the slower-growing true cedars may take 30 to 50 years to achieve that stature.
Environmental Factors That Influence Speed
A tree’s maximum genetic growth potential is only realized when its environmental needs are met, making external factors significant accelerators or inhibitors. Soil composition is a primary element; most cedars require well-drained soil and will struggle in heavy clay or waterlogged conditions, which can starve the roots of oxygen. The preferred soil pH is generally slightly acidic to neutral, with a nutrient-rich composition supporting robust growth.
Water availability is particularly influential in the first few years after planting. Consistent, deep watering helps a young tree establish the extensive root system necessary to support rapid vertical growth later on. Full sun exposure is another requirement for maximizing growth in nearly all species, as insufficient light limits the tree’s ability to photosynthesize energy. Planting in a suitable hardiness zone and protecting young trees from extreme winds or late frosts ensures that the tree can dedicate its energy to growth rather than recovery.