Thuja 'Green Giant'

‘Green Giant’ arborvitae is a large, woody, needled evergreen tree in the cypress family (Cupressaceae). A hybrid cultivar of the western redcedar and Japanese arborvitae (Thuja standishii), it was developed in the 1930s in Denmark and introduced to the United States in 1967 when the U.S. National Arboretum received a specimen. 

This tree does best in a moist, full-sun location with light afternoon shade. It tolerates a wide range of soils. It resists most diseases, insects, periodic droughts, and deer. It does not tolerate salt (spray or salty soils). It is a low-maintenance landscaping choice due to its hardiness and uniform growth habit that requires little to no pruning to maintain an attractive shape. 

‘Green Giant’ has a low-branching, dense columnar-pyramidal habit. Dark green sprays of small, glossy, scale-like needles retain their deep green color through the winter. This tree can grow 3 to 4 feet per year in optimal conditions and reach a mature height of 40 to 60 feet and a width of 12 to 18 feet. It has a lifespan of 40 to 60 years. 

Individuals can be used as specimen plantings. Younger plants may be trimmed into hedges or privacy screens. Groupings planted more closely together, can be used as windbreaks or to reduce noise. This is a popular evergreen choice for landscapes in the southeast United States and is a good alternative to Leyland cypress. Be advised that this plant, like Leyland cypress, can quickly grow very large and become a problem if planted in a space that is inadequate for the tree’s full size.

Quick ID Hints:

• evergreen with a pyramidal habit   

• dense green, scale-like foliage in flat sprays 

• non-flowering

• persistent 0.5-inch, oblong green cones that are brown when matured              

Insects, Diseases, and Other Plant Problems: Bagworms are occasional pests and root rot can occur in poorly drained soils. 

VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.

More information on Thuja.