Plant Profile: Thuja 'Green Giant'

Thuja 'Green Giant' is a robust, needle-bearing evergreen conifer that results from a hybridization of T. plicata and T. standishii, which are the Western Redcedar and Japanese arborvitae, respectively. This hybrid was first cultivated in Denmark during the 1930s and made its way to the United States in 1967 when a specimen was introduced to the U.S. National Arboretum. Its subsequent availability in nurseries sparked greater interest for landscape applications. Characterized by a dense, columnar-pyramidal form, it typically grows to a height of 40-60 feet and a width of 12-20 feet, with a lifespan ranging from 40 to 60 years. The tree features dark green clusters of small, glossy, scale-like needles that maintain their vibrant hue throughout the winter months.

For optimal growth, this tree thrives in moist, sunny environments with some light shade in the afternoon. It is adaptable to various soil types and can achieve growth rates of 3-4 feet annually under ideal conditions. The 'Green Giant' is resilient against most diseases, pests, occasional drought, and deer, although it does not fare well in salty conditions, whether from spray or soil. Its hardy nature and consistent growth pattern make it a low-maintenance option for landscaping, requiring minimal pruning to preserve its attractive pyramidal shape. Younger specimens can be shaped into hedges or privacy screens, while planting them in clusters can serve as effective windbreaks or noise barriers. With hardiness in zones 5-8, this tree is a favored evergreen choice for landscapes in the southeastern United States and serves as a viable alternative to Leyland Cypress.

In terms of pests and diseases, the 'Green Giant' faces few significant issues. While bagworms may occasionally pose a threat, root rot can develop in poorly drained soils. Additionally, it is toxic to grazing animals such as horses, cattle, and sheep.