Green Giant Arborvitae is a large fast-growing evergreen shrub with a dense narrow pyramidal habit. The horizontal to upright flat sprays of rich green foliage remains green throughout the year. Best grown full sun and well-drained soils. Drought tolerant once established, and somewhat tolerant of wet soils.
To learn more about the Green Giant Arborvitae read on.
I. Appearance and Characteristics
Thuja is a genus consisting of six species of coniferous, evergreen trees native to East Asia and North America. The “Green Giant” Arborvitae (Thuja standishii × plicata) variety is an especially fast-growing hybrid cultivar. It is a cross hybrid between the Western Redcedar and Japanese arborvitae. Native to Europe, the D.T. Poulsen nursery of Copenhagen, Denmark chose and introduced the “Green Giant” to the U.S. National Arboretum in 1967.

Photo by David J. Stang
CC BY-SA 4.0
Beloved for its lush aesthetic and ability to propagate, it was distributed widely and confused with a different arborvitae from the same source known as T. occidentalis “Giganteoides.” The clone identity was resolved by Susan Martin, USNA, Kim Trip, New York Botanic Garden, and Robert Marquard, Holden Arboretum by means of thorough nursery inspections, record searches, and “isozyme analysis.” Then the name Thuja “Green Giant” was selected.
Now, it is available at many wholesome nurseries, at retail sources, and by mail-order. Grown as an ideal substitute for Leland cypress in the southeastern United States, this large, needled tree is easy to grow and generally free of pests and disease. Mature trees reach up to 40 to 60 feet tall, growing densely, narrowly, and in a pyramidal habit.
Leaves are small, glossy, and scale-like, opposite and arranged in rows of four, overlapping, creating flat sprays akin to the shape of fans. The bark is dark brown and shaggy. Small, upright seed cones emerge as green and then mature to brown, up to a half-inch long. Unlike some other evergreens, its rich, dense, green foliage does not yellow or brown in winter and only slightly bronzes or darkens.
Coexisting with birds and small animals, this tree creates places for nesting and flower buds, as well as seeds and foliage for food.4 This plant is toxic to grazing animals like cattle, sheep, and horses.

F. D. Richards
CC BY-SA 2.0
The Green Giant Arborvitae was developed with enhanced pest-resistant features, making it less appealing as a food source for deer. However, it’s important to note that in situations where other food options are scarce, deer may occasionally feed on these trees.
II. How to Grow and Care
Sunlight
“Green Giant” Arborvitae prefers full sun. It will tolerate part shade and actually thrives in some light afternoon shade in hot summer climates.
Watering
Regular watering is important, especially for young plants and in dry conditions. Avoid extreme dry soil in the fall, which can cause the evergreen foliage to dry out in winter.
Soil
Able to grow in a range soils such as poor soil and clay, it does best in moist, fertile, well-drained loams. Avoid wet soil that does not drain well and exposure to spray or salt.
Fertilizing

Photo by David J. Stang
CC BY-SA 4.0
Apply a balanced, slow-release fertilizer in early spring. Over-fertilization can harm the plant, so follow the recommended rates.
Planting Instructions
Put garden soil in a wheelbarrow or on a tarp. Mix the garden soil with equal amounts of mulch, peat moss,
and potting soil. Place plant in hole and adjust for aesthetics. Hold in place while adding more soil, until the
hole is completely filled. Push soil down until firm. Do not plant the shrub deeper than it has already been
growing. Water well immediately after planting. Mulch evenly to a depth of 2-3 inches being sure to stay at
least 4” away from its trunk.
Pruning
Covered in dense, dark, evergreen foliage from the ground up, the “Green Giant” arborvitae needs little to no pruning or shearing. Growing elegantly and consistently, it only needs to be pruned if necessary or for aesthetic reasons. Shear into a desired shape and size, and maintain it throughout the warmer months.
Propagation
Propagate the tree from stem cuttings from July through March. Root cuttings under mist with bottom heat (3000–8000 ppm IBA).
Pests and Diseases

Photo by David J. Stang
CC BY-SA 4.0
Fortunately, this variety is more resistant to deer than most arborvitae and it has no major insect or disease issues. Keep an eye out for scale, rots, and bagworm in poorly drained soils.
III. Uses and Benefits
Widely used for creating fast-growing privacy screens, windbreaks, and hedges. It’s also used as a specimen plant due to its majestic size and shape.
Offers rapid growth, privacy, and an easy-care nature. It’s also resistant to many common pests and diseases, making it a resilient landscaping choice.