Grow Guide for Thuja ‘Green Giant’

thuja green giant privacy pond

A row of Thujas line a pond to create the perfect look

Thuja Green Giant has become one of the most popular trees for creating a living screen. It’s no wonder: Green Giant is an evergreen throughout the year; it is adaptable to most soil types; it is tolerant of light shade and of moderate drought; and it grows extremely fast, putting on 3-5 feet of height per year. A row of Green Giants will quickly create a privacy screen that blocks the wind and snow, and blocks the view. The dark green foliage of the green giant arborvitae can grow in a wide range of soils.

Thuja ‘Green Giant’ is a large tree hybrid between the American native, western redcedar (Thuja plicata), and the Asian native, Japanese arborvitae (T. standishii). Thuja ‘Green Giant’ grows faster, and is said to stay greener in winter than either parent. It is more cold hardy than the Japanese species, and more tolerant of a lethal fungus (Didymascella thujina) than the American species. Green Giant is capable of reaching up to 60 feet tall, with a 20 feet wide spread across its bottom.

In cultivation, Thuja ‘Green Giant’ is superior to most all other evergreen conifers.

thuja green giant privacy hedge

Thujas create excellent privacy between neighboring houses

Because of its fast growth rate, Green Giant is among the best choices for a quick evergreen hedge, privacy fence, or wind and snow break. A row of Green Giants along your property line will protect more vulnerable plants and your home from damaging winds.

Line the driveway with a row of Green Giants to create a barrier that keeps drifting snow away. With lower branches that will eventually extend way out beyond the trunk, Green Giant has a tall, imposing pyramidal habit. However, it can be kept compact by regular pruning. In fact, Green Giant responds well to clipping and pruning, even to moderate shearing.

Site Selection

Green Giant performs best on moist, fertile, well-drained, loamy soils in full sun to part shade. It will not survive on soils that stay soggy, and it doesn’t like highly compacted soils. In USDA planting zones 5 and 6, full sun is best; in warmer climates, a little shade, especially in the afternoon, won’t hurt.

thuja green giant focal point

Three Thujas generate an amazing statement piece that will be the center of attention in your landscape

As a majestic sentinel tree, Green Giant has few equals. A pair of Green Giants on opposing sides of the yard will frame your landscape in grandiose form. In a larger yard or park, position a cluster of three Green Giants for a positively regal focal point.

For a living privacy screen, a wind break, or a snow break, position Green Giants 5-6 feet apart. Or, better yet, plant them in two rows, 4 feet apart, with the trees staggered 8-10 feet apart within each row. The row(s) should be at least 6-8 feet away from any building, driveway or road.


If your soil is very compacted, you should consider tilling before digging the individual planting hole(s). You can plant anytime of the year, but the best time for planting a new tree is spring, before it gets too hot, while still allowing a whole growing season before winter to establish a strong root system.

thuja new planting

Newly planted Thujas will need plenty of water the first growing season to establish strong roots

Before starting, thoroughly water the soil in the nursery pot so that the Green Giant’s roots are fully wetted. Place the pot on its side and slide the root ball out. If the plant is stuck, you can slip a long-bladed knife around the inside edge to loosen it. Gently loosen some of the roots along the sides and bottom of the root mass, and pull them outward so they are not encircling the root mass. It shouldn’t be necessary to prune any of the roots unless they are wound around the circumference of the pot. In that case the offending roots should be shortened so that when they are in the ground they will grow outward and not continue growing in a circle.

Dig a hole twice as wide and a little deeper that the container the Green Giant arrived in. Do not add any fertilizer or amendments. Mound up some soil in the middle of the hole, 3-6 inches high, and place the center of the root mass on top of the mound, spreading roots out in all directions around the hole. Begin filling in the hole. Backfill until the top of the root mass is at the same level it was in the original nursery pot, never lower. You may have to pull the plant up as you backfill. When the hole is half filled, give it a good soaking of water. When the water has drained, readjust the depth of the stem if necessary and finish filling in the hole. Gently tamp the soil down with your hands.

mulch your thujas

Mulching is essential to maintain moisture for newly planted trees

Build a 3-6 inch high dike of soil on the surface around the outside of the root zone. This will impound water over the roots as it sinks into the soil. Water thoroughly. Spread an organic mulch 3-6 inches deep over the root zone and beyond to help hold in soil moisture and prevent weed growth. You can use hay, straw, leaves, pine needles, bark or wood chips, grass clippings, or compost. Keep the mulch 3-4 inches out from the trunk. Do not fertilize at this time.

Water every day or two for the first 2-3 months, until the plants are established. After that, they should get one inch of water every week or ten days. If you’re having a dry spell, or your soil is very sandy, you should water more often.

The most common reason for any newly planted tree to die is lack of enough water.


Your Green Giant will need about an inch of water, either from rainfall or irrigation, per week. Renew the mulch layer as needed to protect the roots from drying out, freezing, or overheating, and to smother weeds. Use an organic mulch that will decompose and add nutrients to the soil. Try to maintain a mulch layer 3-6 inches deep around the tree at all times, but keep it a couple inches away from the trunk itself.

Fertilize Green Giants each spring with a balanced fertilizer, or one with a higher concentration of nitrogen. Slow release fertilizers are best like the one Perfect Plant’s offers. Follow label directions and be careful to not over-fertilize.

Without any pruning, Thuja ‘Green Giant’ will grow into a stately pyramidal shape with foliage that stays dense all the way to the ground. After its first year of growth, it can be pruned to fit your needs. To maintain a low hedge shape, you will need to shear several times during the growing season.

You simply cannot go wrong with Thuja Green Giant – they are the fastest growing evergreen trees, can provide privacy in as little as a year, and Perfect Plants has many size options to get you the exact tree you need!

Contact us with any questions you may have.

Happy planting!