Arborvitae (genus Thuja) is an evergreen shrub or tree known for its dense, scale-like foliage. Homeowners often choose these plants to create natural privacy screens, windbreaks, or formal hedges due to their upright, pyramidal growth habit. A successful planting requires preparation and technique to ensure the plant transitions smoothly into its new environment and promotes robust root development and longevity.
Selecting the Site and Timing
Choosing the correct location and planting window sets the stage for the Arborvitae’s long-term health. The ideal time to plant is during the cooler periods of the year, either in early spring after the last hard frost or in early fall well before the ground freezes. Planting during these times allows the roots to establish themselves without the stress of extreme summer heat or intense winter cold.
Arborvitae performs best when situated in an area that receives full sun, meaning a minimum of six hours of direct sunlight daily, though most varieties will tolerate partial shade. Proper soil drainage is extremely important, as the plant’s roots are sensitive to consistently soggy conditions, which can quickly lead to root rot. If your native soil is heavy clay, amending it with compost or other organic material before planting is a recommended step to improve aeration and water percolation.
When planting multiple Arborvitae, consider their mature width to determine proper spacing. Providing adequate room—typically three to four feet between the centers of the plants—ensures good air circulation and reduces competition for water and nutrients as they mature. Sufficient space allows the foliage to remain dense and green from top to bottom.
Executing the Planting Steps
Begin by digging a hole two to three times the width of the root ball, but only as deep as the root ball itself. This width provides loose soil for the initial outward growth of new roots, and the specific depth prevents the tree from settling too low in the ground.
Before placing the plant, gently remove it from its nursery container and inspect the root ball. If the roots are tightly matted or circling (root-bound), use a sharp tool or your fingers to lightly score or tease them outward. This encourages them to grow into the surrounding soil. For balled-and-burlapped plants, remove all wire cages, twine, and burlap completely once the plant is situated in the hole.
Position the Arborvitae so the root flare—the point where the trunk widens just above the roots—is positioned at or slightly above the surrounding grade level. Planting too deeply is a common error that can lead to trunk rot and root suffocation, hindering the plant’s ability to thrive. You can firm the soil at the base of the hole, ensuring the plant remains stable at the correct height before backfilling begins.
Use the native soil, perhaps amended with a small amount of compost, to fill in the hole around the root ball. Backfill in stages, gently tamping the soil with your hands to eliminate large air pockets without compacting the soil excessively. Once the hole is about two-thirds full, water the area thoroughly to further settle the soil and eliminate small voids around the roots. Finish filling the hole, ensuring no soil is placed over the root flare.
To direct future irrigation precisely to the root zone, create a small, circular berm, or ridge of soil, around the outer edge of the planting hole. This ridge helps capture water and prevents it from running off, allowing it to slowly soak down to the newly placed roots.
Essential Care for Establishment
The first growing season is a vulnerable period, requiring consistent moisture management to help the Arborvitae establish a strong root system. Immediately after planting, give the tree a deep soaking to saturate the entire root ball and surrounding backfill. Following this initial watering, the goal is to maintain consistently moist, but never waterlogged, soil.
For the first few months, a newly planted Arborvitae typically requires deep watering two to three times per week, depending on temperature and rainfall. The water should penetrate the soil to the depth of the root ball, encouraging roots to grow outward and downward. You can check the moisture level by inserting a finger two inches into the soil near the root ball; if it feels dry, it is time to water.
Applying a two to three-inch layer of organic mulch, such as shredded bark, helps conserve soil moisture, regulate soil temperature, and suppress weeds. It is important to apply the mulch in a wide ring, keeping it several inches away from the trunk and root flare to prevent the accumulation of moisture against the bark, which can lead to decay.
Initial fertilization is not necessary, as the goal is root establishment, not rapid top growth. If desired, a slow-release, balanced granular fertilizer can be applied according to package directions, but heavy feeding is discouraged during the first year.
Temporary staking is rarely needed for smaller specimens. If a taller plant is exposed to high winds, use broad, flexible material to secure it for no more than one to two growing seasons. This allows the roots to anchor the tree naturally.