How to Landscape With Green Giant Arborvitae

Green Giant arborvitaes make a good outdoor Christmas tree.

Introduced by the National Arboretum in 1967, Green Giant arborvitae (Thuja plicata "Green Giant") is an award-winning large conifer. Topping out at 40 to 60 feet tall and 10 to 20 feet wide, Green Giant is a fast grower, capable of adding 3 feet of new growth each year once it's well established. The tree is hardy in U.S. Department of Agriculture plant zones 5 through 8. You have several options on how to use Green Giant in the home landscape.

Things You'll Need

• Fertilizer
• Pruners
• Insecticide (optional)

Instructions

1. Plant a Green Giant arborvitae in full sun in moist, well-drained soil. It tolerates partial shade but the trees lose their dense pyramidal shape and are much less attractive. For fastest growth, water the tree often enough to keep the soil moist and feed it in late winter and midsummer with a shrub fertilizer.

2. Plant multiple specimens 15 feet apart to use Green Giant as a wind screen or tall hedge. For the best wind resistance, plant the trees in staggered rows.

3. Install just one tree in your front yard as a living Christmas tree. If necessary, shape the tree gently when young to accentuate its natural conical shape.

4. Top the shrub when it reaches the desired height if you're growing it as a medium-sized hedge. Since this cultivar naturally grows so tall, for best results shape the hedge while the trees are still young for the most natural appearance. Trim the hedge so the bottom is wider than the top to keep the foliage dense to ground level.

5. Use Green Giant as the focal point in a mixed border. Surround it with rounded plants that contrast with its conical shape. It also makes a good background for gold-colored evergreens and deciduous trees and shrubs with brilliant fall color.

Tips & Warnings

• There's some confusion with the proper botanical name for this plant. Some resources list it as T. plicata "Green Giant" and some as T. standishii x plicata "Green Giant," since it's believed to be a Danish hybrid between two Thuja species. Green Giant is also marketed under the cultivar name Spring Grove.

• Like most arborvitae, Green Giant is susceptible to bagworms. Inspect your trees frequently for the insects. Small numbers can be picked off by hand, but heavy infestations must be treated with an insecticide. Don't delay -- bagworms can defoliate and kill a tree in a few weeks.

References

• North Carolina State University: Thuja Plicata
• University of Connecticut: Thuja Plicata
• University of Georgia: 2007 Tree Winner -- Green Giant Arborvitae

Resources

• Read this Article in Spanish
• U.S. National Arboretum: USDA Plant Hardiness Zone Map