The green giant arborvitae is a spritely evergreen tree that adds wonder and beauty to all kinds of landscaping arrangements. However, since these trees grow exceptionally quickly, it’s helpful to understand how to space them and accommodate their growth. Otherwise, you risk evergreens growing out and suffocating the roots of other plants.
In this article, I’ve set out everything you need to know about green giant arborvitae spacing and growth. Plus a close-up look at maintenance and expert tips about taking care of these majestic giants.
Green Giant Arborvitae Size
According to the Arbor Day Foundation, the Thuja is typically 50 to 60 feet tall at maturity, making it one of the tallest evergreen trees on the planet. Some sources indicate that they can even grow to a staggering 75 feet tall and 25 feet wide.
What is even more distinct about the green giant, however, is its yearly growth rate. The tree will grow around 2 to 3 feet per year on average and as many as 5 feet in irregular cases.
It’s because of the evergreen’s rapid growth rate and high maximum height that makes green giant arborvitae spacing tricky. However, other aspects of the green giant’s size also need to be considered before planting.
How Wide Do Green Giant Arborvitae Get?
When fully mature, these trees have an average spread of 12 to 20 feet, making them exceptionally wide compared to other evergreens. The combination of the tree’s height and width gives it an iconic and protective conical shape. Understanding the spread of the green giant is especially important if you’re interested in using it on your property for hedging or screens.
Thuja Green Giant Root System
The arborvitae is a resilient tree when it comes to soil types. It can tolerate finely-ground and rocky soils but does not grow well in wet, marshy, or salty areas. Because of this, it’s critical to plant the green giant in areas with good drainage and little clay so that the soil is properly irrigated.
Thuja roots are thin and fibrous but can spread to great lengths, often coming close to the tree’s dripline (or outermost circumference). A green giant evergreen needs as much room for its roots as it does for its width to avoid overcrowding. Otherwise, the tree may not be able to get enough water due to invasive plant roots.
In terms of depth, the mature arborvitae needs about 18 to 24 inches of soil for its roots to extend downward. Planting the tree in soil that is too shallow could cause anchoring and health issues, including waterlogging.
Green Giant Arborvitae Spacing For Planting
The Thuja looks stunning in many different landscaping arrangements, either solo or together with other trees. As a single specimen, it stands tall as a great accent, but with others, it creates more complex formations. However, to avoid root choking and harming the trees, proper care should be taken when spacing them.
Let’s look at some examples of green giant arborvitae spacing and their specifications.
Spacing For Hedge
Many sources rank the Thuja green giant as the number one tree for hedging due to its width and growth rate. There are many ways to space a set of Thuja hedges, depending on your desired outcome.
Planting the trees too close together will result in hedges that are thinner on the bottom than they are on the top. For a hedge, it is more ideal to have trees thicken towards the bottom since the top will be trimmed and shaved. Thuja green giants will need at least 3 feet of distance apart for the proper thickness.
Spacing them 3 feet apart will create a very dense hedge, and so if you want a thinner hedge, 5 feet apart is a solid choice. However, hedge spacing depends greatly on the desired height of your arrangement. If you want hedgerows over 6 feet tall, then spacing your arborvitae 6 or 7 feet apart will give the trees enough room to grow.
Alternatively, for a screen or barrier, 6 to 8 feet apart is ideal. Since screen trees are usually untrimmed, putting the arborvitae this close together will create a thick screen while keeping the trees uncrowded. After pruning, your screen or hedge will become even thicker, so plan for the look that you want.
Planting From Buildings
It’s important to never plant the Thuja green giant near buildings or structures including houses, power lines, and large garden fixtures. Due to the tree’s rapid growth rate and maximum size, there is a danger that over time, matured roots or branches could cause structural damage to buildings and structures.
If you’re planting a green giant as a specimen tree, make sure to distance it at least 15 feet from structures and other plants.
How To Plant Green Giant Arborvitae
Before planting a green giant, map out an area that fits its sizing needs. The area should accommodate the tree’s width and height. The soil should have little clay, good drainage, and enough room for the mature tree’s roots to stretch into the ground. The area should be a good distance away from any water sources or wet areas.
In addition, the area must meet the tree’s needs for sunlight. The Thuja green giant thrives best in areas with full sun and partial shade where the tree can experience over four hours of direct sunlight per day.
Once you purchase an arborvitae sapling, remove it from the pot and gently shake away excess dirt until the root ball is exposed. You will want to dig a hole for the tree that is about 1 inch deeper and 3 times wider than the dimensions of the root ball. This is because arborvitae roots tend to spread more horizontally outward than downward.
If you dug a hole of the correct size, the sapling will appear about as tall in the hole as it was in the pot. Over a few rounds, fill the hole around the sapling and stamp it down firmly with your foot. Eventually, the tree will be buried and sufficiently anchored in the firm soil.
Once the tree is in place in its new hole, cover the top of the space with mulch to ward away unwanted weed growth, to help retain moisture, and to add nitrogen to the soil.
Using an arborvitae fertilizer periodically will help roots to become established and ensure that lush green vibrancy that is synonymous with these beautiful evergreens.
I am a big fan of Jobe’s evergreen fertilizer spikes. They are high in nitrogen and offer a slow-release feed. Plus they are mess-free and one application will last for the season.
It will take a few growing seasons before the tree’s roots begin to stretch into the surrounding soil. Until then, continually keeping the tree watered thoroughly once per week will help it reach maturity.
When To Plant Thuja Green Giant
The Thuja is a particularly resilient tree in terms of drought tolerance, rainfall, and soil conditions. It grows best inside Hardiness Zones 5 through 7 which encompass most of the central, northeastern, and northwestern United States. It will not likely grow comfortably in any other zones, so I advise that you seek out a different evergreen if you live in significantly colder or warmer areas.
While the Thuja’s conical shape helps it defend against wind, rain, and snow, a young sapling is not as well-equipped for that. I advise planting an arborvitae sapling at the very beginning of spring when the weather is fair. This will give the tree plenty of time to take root before tough storms and colder weather arrive later in the year.
You do not need to fear planting the green giant in areas with pest issues, as this tree is naturally resistant to many types of common arboreal pests, as well as deer browsing. In addition, the tree is resistant to drought once it has matured, so do not be deterred if you live in an area with occasional heat waves.
A Thuja green giant is particularly stunning in the winter season when its foliage bronzes. Because of this, the conifer is a popular choice for Christmas trees and landscaping in cold areas. If you want arborvitae for a breathtaking Christmas tree, I advise planting it two years before the year you plan to use it. By then, it will have a rich green color and beautiful stature.
In addition, it is a functional windbreak that can shield other trees and plants from the wind once fully grown. Its conical shape helps it resist gusts, rain, and snow while sheltering other plants and trees.
Green Giant Arborvitae Growth Rate
This conifer is praised and frequently used in hedging because of its speedy growth rate of several feet per year. The average green giant will grow at least 24 inches per year and in some cases as many as 60 inches in one year. This extreme rate is contingent on each of the tree’s needs being met, including sunlight, spacing, and drainage.
How To Make Green Giant Arborvitae Grow Fast
Nothing is more of a setback to your tree’s growth than improper care. Make sure that you use a mulch to minimize weeds and don’t overwater the tree. If the tree has proper care during the early seasons, it will continue to grow strongly into maturity. However, there are also some specific practices and products that can expedite the green giant’s growth.
For instance, using nitrogen-rich evergreen fertilizer is effective during the first few seasons of the tree’s growth. Use a fertilizer that is easy for the young trees to absorb through their roots such as a fertilizer spike or water-soluble fertilizer.
This will stimulate growth and prevent root burn. However, too much is not a good thing. Be sure to carefully read the package instructions and only apply fertilizer once every two to four weeks.
After the first few growing seasons, granular fertilizer becomes more effective and economical for increasingly growing trees and expanding growth rates. Granular fertilizers typically only need to be applied once per season.
If you want a specimen tree that will grow to its maximum width and height, avoid pruning a young tree. Pruning parts of the tree sends a biological signal that slows growth, so only prune if you’re interested in having shaped arborvitae hedges or once your evergreen is fully mature.
Green Giant Arborvitae Care
Green giants have several natural advantages such as pest resistance, weather resilience, and drought protection. However, they aren’t invincible, especially in their early stages. A green giant is capable of caring for itself almost entirely at maturity but will need special care as a sapling. Here are some of the most important tips for raising these trees.
How Often To Water Green Giant Arborvitae
Most commonly, green giants only need to be watered once per week. However, if you live in Hardiness Zone 7 and experience hotter summers, consider watering your arborvitae twice per week. During the sapling stage, these trees are highly susceptible to having their roots dry up, heavily stunting their early growth.
Adversely, too much water is another problem this plant faces. The Thuja has very salt-sensitive roots and is prone to waterlogging. If you aren’t growing the trees in areas with ideal soil drainage, the roots risk getting drenched and experiencing root rot or fungal infections.
Once it reaches adulthood, the green giant doesn’t need to be watered unless the planter wants to promote more growth. Although the tree is drought-resistant, it can still dry up and wither during hot months, so do not hesitate to water the tree adequately during heat waves.
Green Giant Arborvitae Fertilizer
Many sources suggest not fertilizing sapling arborvitae until after a few growing seasons. Others suggest only using water-soluble fertilizers for the first few seasons. Once the trees have taken root, they’re ready for a granular fertilizer a few times per year.
Many blends and brands will effectively do the job, but let’s discuss the specifics of an ideal evergreen fertilizer.
Primarily, growing trees need a lot of nitrogen. A fertilizer’s three-number code indicates the ratio of its contents, and the first of these numbers is its nitrogen content. Blends with high nitrogen ratios such as 16-4-8 will supply the trees with this need. However, the other numbers in this series—phosphorus and potassium—are also important, albeit in smaller amounts.
Many brands have fertilizers designed for conifers, evergreens, and flowering trees. You can find your favorites at all kinds of garden supply stores. I advise that you check the nutrient content of any fertilizer before buying, as it’s far more important than a brand name.
The package of fertilizer you get will describe applying instructions and timetables. In general, if you use water-soluble fertilizer on a young evergreen, you’ll want to apply it in early spring. By midsummer, it’ll be ready for a granular fertilizer, and you can apply this fertilizer again in late winter to stimulate its growth in the spring.
Common Thuja Green Giant Tree Problems
Lastly, I’ll address some problems that are frequently faced by Thuja growers and how to solve them.
Final Thoughts: Green Giant Arborvitae Spacing
Now you know how to plant, space, and maintain the versatile and beautiful Thuja green giant. While it is a relatively self-supporting tree in adulthood, it can be a very labor-intensive and even fickle plant in its early seasons. Be sure to raise it with love and care and to stay attuned to its conditions and needs.
A Thuja green giant will make an excellent addition to your landscape through hedges, screens, or even a majestic single specimen. Plant one in the early spring and watch them grow into stunning adults. But, remember to follow the correct Green Giant Arborvitae spacing!