Green Giant Arborvitae Thuja 'Green Giant'

Green giant arborvitae is a large, needled, evergreen, conifer tree that is a hybrid cultivar of T. plicata and T. standishii (a cross between the western red cedar and Japanese arborvitae, respectively). This hybrid was developed in the 1930s in Denmark and was introduced to the U.S. in 1967 when the U.S. National Arboretum received a specimen. Later availability to nurseries increased interest for use in landscapes. Its low-branching, dense columnar-pyramidal habit reaches a mature height of 40-60 feet and width of 12-18 feet with a lifespan of 40-60 years. Dark green sprays of small, glossy, scale-like needles retain their deep green color through the winter.

This tree does best in a moist, full-sun location with light afternoon shade. It tolerates a wide range of soils and, in optimal conditions, can grow 3-4 feet per year.

It resists most diseases, insects, periodic drought, 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 pyramidal shape. Younger plants may be trimmed into hedges or privacy screens.

Groupings, planted more closely together, are also used as windbreaks or to reduce noise. Preferably, plant group of three Green Giant arborvitae and mix with other screening trees to avoid creating a monoculture in the event of a disease outbreak. Hardy in zones 5-8 makes this a popular evergreen choice for landscapes in the southeast U.S. and is also a good alternative to Leyland Cypress.

Great Giant Arborvitae is a versatile, easy to grow, and low-maintenance conifer evergreen for the home landscape. It may be used as a specimen, hedge, or screen. 

Seasons of Interest:

Bark:   Year-round                   Foliage:  Year-round            Fruits: Year-round

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:  No serious problems.  Bagworms are occasional pests and root rot can occur in poorly drained soils. Toxic to grazing animals such as horses, cattle, and sheep.

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.