Arborvitae (Thuja) are popular evergreen conifers valued for their dense, year-round foliage, making them ideal for privacy screens and hedges. While many common varieties are naturally moderate to slow growers, certain selections like ‘Green Giant’ can add two to three feet of height annually under optimal conditions. Accelerating the growth rate of any arborvitae requires moving beyond basic survival care to providing an environment where the plant can thrive without limitations, combining proper environmental setup, consistent maintenance, and proactive problem-solving.
Establishing the Right Environment
The foundation for fast growth begins with selecting the correct site and proper planting technique. Arborvitae perform best when they receive at least six hours of direct sunlight daily, which maximizes photosynthetic output and leads to denser, more vibrant foliage. Plants situated in too much shade often become sparse or leggy as they stretch to find light.
Proper soil and drainage are equally important, as these trees prefer moist but well-draining conditions and suffer quickly from root rot in heavy, waterlogged clay. When planting, the hole should be two to three times wider than the root ball, but no deeper. Set the tree so the root flare—the point where the roots begin to spread from the trunk—is level with or slightly higher than the surrounding soil line to prevent the trunk from sitting too deep.
Fueling Rapid Growth Through Inputs
Once the environment is established, consistent maintenance acts as the direct fuel for accelerated growth. Deep, consistent watering is important because arborvitae have naturally shallow root systems highly susceptible to drying out. A deep soak encourages roots to grow downward, supporting a robust root system capable of sustaining rapid top growth.
During the first few growing seasons, newly planted trees require deep watering two to three times a week, especially in hot or dry weather, to keep the soil consistently moist but not soggy. The goal is to apply enough water to penetrate the soil 8 to 12 inches deep. This can be achieved by using a soaker hose or letting a regular hose trickle slowly at the base for an extended period.
Fertilization provides the concentrated nutrients necessary for producing a large volume of new foliage. Arborvitae benefit most from a high-nitrogen fertilizer, such as a 20-15-15 or 10-5-5 blend, since nitrogen is the primary nutrient required for leaf and stem growth. Apply this fertilizer in early spring before new growth emerges to provide a boost for the active season.
Using a slow-release granular formula is preferable because it delivers nutrients steadily over the growing season and minimizes the risk of burning the shallow roots. Avoid fertilizing new plantings for the first year or two, allowing the plant to focus its energy on root establishment before pushing extensive top growth. A layer of organic mulch, applied 2 to 3 inches deep and kept several inches away from the trunk, helps regulate soil temperature and conserve moisture.
Identifying and Removing Growth Roadblocks
Even with perfect inputs, growth can be significantly slowed or halted by external threats that divert the plant’s energy from development to survival and repair. Common pests like bagworms and spider mites drain the plant’s resources by feeding on the foliage. Bagworms create spindle-shaped silk sacks and can defoliate portions of the plant, while sap-sucking spider mites cause foliage to appear stippled or bronzed.
Proactive monitoring is necessary, and infestations require quick treatment, such as hand-picking bagworms or applying insecticidal soap or horticultural oil for mites. Environmental stressors, particularly winter burn and deer browsing, also act as major roadblocks. Winter burn occurs when the plant loses moisture through its foliage faster than its roots can absorb it from frozen ground.
Applying an anti-desiccant spray in late fall creates a protective coating on the needles, reducing water loss during the winter months. Deer frequently browse arborvitae foliage, especially when other food sources are scarce, requiring the plant to spend energy on repairing the damage. Physical barriers, such as tall fencing, offer the most effective long-term protection, though consistent application of deer repellents can mitigate browsing pressure.
Light, selective pruning is necessary only to remove dead or diseased wood to redirect energy to healthy growth points. Heavy shearing should be avoided as it slows the overall growth rate.