Thuja x ‘Green Giant’ Green Giant Arborvitae

Green Giant Arborvitae is a hybrid between Western Red Cedar (Thuja plicata) and Japanese Cedar (Thuja standishii). It was bred and selected in Denmark, then a sample was sent with some other selections to the National Arboretum in Washington, D.C. Its fast growth and large size quickly set it apart from the rest, but some poor record-keeping obscured its true hybrid identity for several more decades until the technology existed to determine its parentage. Green Giant demonstrates the concept of “hybrid vigor”, where the offspring surpasses both parents in size and growth. Like other Arborvitae, Green Giant is evergreen with feathery foliage in a pretty green color that provides year-round interest and privacy. The main thing that sets Green Giant apart from other types of Arborvitae is its fast growth rate.

Care and Maintenance

While most Thuja varieties can grow anywhere from 6”-2’ per year, Green Giant has been known to put on 3-4’ of new growth in a year! It also responds well to shearing, making it a great choice for a large privacy hedge. Without any pruning, Green Giant can reach towering heights of 50’ tall or more. With pruning, it would be easy to maintain a Green Giant hedge at anywhere from 10-20’ tall. Another wonderful feature of Green Giant is its tolerance of heat and humidity. Most types of Arborvitae do not thrive in the Southeastern US, but Green Giant is a great option. As long as it has plenty of water, it can withstand very warm summers. Thanks to its Western Red Cedar parentage, Green Giant also has some deer resistance. Very hungry deer may eat it, but generally they will avoid it. Green Giant has almost no disease issues and is extremely easy to grow. With yearly pruning, you can quickly have a thick, tall privacy hedge for optimum screening.

Green Giant Arborvitae is an enormously popular landscaping tree widely used as a hedge, privacy screen, and windbreak. A Danish nursery in Copenhagen developed it in the 1930s from a cross between Western redcedar (Thuja plicata) and Japanese arborvitae (Thuja standishii). They sent a single specimen to the U.S. National Arboretum in 1967, and it exhibited such outstanding qualities of vigor and fast growth that it was propagated for the landscaping industry and named ‘Green Giant.’ In 1998, the Pennsylvania Horticultural Society recognized it with the Gold Medal Plant Award for its excellent qualities. Today, it is widely distributed and can be found in nurseries, garden centers, and online.

Uses in Landscaping

Green Giant is a tall, pyramidal tree with dense, green sprays of glossy, scale-like foliage on slightly upturned branches that hold their color throughout the winter. It can grow 3′-5′ per year and reach 50′ high and 5′ wide in 10 years, making it one of the fastest-growing conifers. It is a stunning specimen tree or can be used in a grouping, such as three trees together in a corner of the property, or grown in a line along a driveway, as a privacy screen on the property line, or as a windbreak. This handsome tree grows naturally into a tall, pyramidal shape but can also be pruned into a beautiful, dense, low-maintenance hedge.

Green Giant Arborvitae thrives in full sun but will appreciate some light shade in the hot afternoon sun of the southern zones. It is adaptable to a wide range of soils as long as they are moist and well-draining, but it does not do well in wet areas or salt spray. It needs to be watered at planting and irrigated regularly for the first year of establishing.

Companion Plants

Companion plants for Green Giants can make a colorful and textural contrast against the dense, dark green foliage. Shrubs, like hydrangeas, rhododendrons, spiraeas, crape myrtles, and azaleas, stand out with their bright flowers, and small trees like redbuds and dogwoods are a cloud of color against the solid green of the arborvitaes. Ornamental grasses, like Hakone or Japanese Forest grass, add a sense of movement and texture in front of the trees. Flowering perennials such as hostas, daylilies, peonies, and Russian sage bring a pop of color against the dark green backdrop.

In addition to its many outstanding qualities, Green Giant Arborvitae is an excellent cover for birds and small animals. It is pest- and deer-resistant and can withstand heat, humidity, and drought, which makes it an exceptional alternative to the Leyland Cypress in the southern states. It is also a great choice in the northern areas of its 5-8 hardiness zones due to its resistance to cold, ice, and snow.