The correct spacing for cedar trees is a variable calculation based on the specific species planted and the desired outcome in the landscape. Planting these evergreens at the right distance influences their long-term health, growth rate, and ability to form the intended barrier or specimen shape. Insufficient space leads to poor air circulation, competition for nutrients, and disease. Conversely, too much space leaves unwanted gaps that take years to fill in.
Identifying Cedar Types and Growth Habits
The name “cedar tree” is commonly used in landscaping for several distinct genera of coniferous evergreens. The majority of trees sold as cedars for screening are actually Arborvitae (Thuja) or Junipers (Juniperus), not true cedars (Cedrus). True cedars, such as the Deodar Cedar (Cedrus deodara), are large specimen trees that can reach widths of 40 to 50 feet, requiring substantial space to develop their characteristic broad form and weeping branches.
Arborvitae are the most popular choice for hedges and screens, coming in two main types: columnar and wide-spreading. Narrow varieties like ‘Emerald Green’ Arborvitae (Thuja occidentalis ‘Smaragd’) grow in a tight, vertical cone, reaching a mature width of three to four feet. Fast-growing hybrid varieties like ‘Green Giant’ Arborvitae (Thuja standishii x plicata ‘Green Giant’) develop a wider pyramidal shape, often spreading 12 to 18 feet at maturity. The Eastern Red Cedar (Juniperus virginiana) can mature to a width of 8 to 20 feet, often used in windbreaks or wildlife plantings.
Calculating Spacing Based on Goal
The spacing calculation is determined by whether you intend to create a dense hedge or allow the tree to grow as a standalone specimen. For a dense privacy screen, the goal is to have the canopies overlap slightly at maturity, forming an impenetrable green wall. To achieve this, the planting distance is typically calculated as one-half to two-thirds of the tree’s expected mature width.
Planting at this closer distance forces the trees to grow upward and inward, creating a uniform barrier more quickly. When planting for a specimen tree or a loose windbreak, the spacing must accommodate the full mature width of the tree to allow for maximum sun exposure and air circulation. Specimen trees should be planted at a distance equal to or greater than the full mature diameter to ensure they develop their natural shape. Adequate air flow between individual plants is necessary to reduce moisture buildup on the foliage, helping to prevent fungal diseases.
Specific Spacing Measurements
Spacing for tall, narrow varieties like the ‘Emerald Green’ Arborvitae should be between two and three feet apart for a dense privacy screen. This close spacing encourages quick fill-in for a formal hedge, as the mature width is only about four feet. If the ‘Emerald Green’ is intended as a vertical accent or specimen, it should be planted at least eight feet apart.
For the wider ‘Green Giant’ Arborvitae, the spacing requirement is larger. To form a solid privacy screen, these trees should be planted five to six feet apart, allowing the 12-to-18-foot mature width to eventually knit together. When planting ‘Green Giants’ as individual accent trees or for a less formal windbreak, a spacing of 15 to 20 feet is necessary. Eastern Red Cedar is often used for wider windbreaks and can be spaced 10 to 15 feet apart.
Successful Planting and Initial Care
Proper planting technique is essential for the long-term health and establishment of the tree. The planting hole should be dug two to three times wider than the root ball but no deeper. This wide hole provides loose soil that encourages the developing roots to spread horizontally into the surrounding native soil.
It is necessary to ensure the top of the root ball is level with the surrounding grade or slightly above it to prevent the tree from settling too deep. Planting too deeply is a common mistake that can lead to suffocated roots and eventual tree decline. Immediately after planting, water the tree thoroughly to settle the soil and eliminate any air pockets around the root system. Consistent watering is required for the first growing season, especially during dry periods, to establish the root system, keeping the soil moist but never saturated.