When to Plant Thuja Green Giant Arborvitae?

Written by

William Golder


Dorian Goodwin

when to plant thuja green giant

Do glass windows make you feel exposed? Does your property require extra protection from wind and snow?

To solve these issues, you may have thought of installing curtains or revamping your home walls, but there’s another fix that’s also effective: planting Thuja green trees.

Thuja shrubs will provide cover year-round with their dense foliage, thereby enhancing both the privacy and weather protection of your residence.

But when to plant Thuja green giant? The best time of year for this task is spring or fall when there’s no frost. Usually, you should grow them in April or August and September, but the estimate will change depending on your regional frost dates. Read below for more details.

When to Grow Thuja Green Giant

1. In spring, after the last frost

thuja-green-giant-spacingThe best time to plant Thuja green giant is in early spring. This season allows tree roots to establish themselves without interference from the summer heat and winter cold.

Moreover, the ground should be warming up by then, allowing the soil to be tilled and dug more easily.

Now, you may think: “These benefits all sound nice, but how do I take advantage of them?”

Very easy. Look up the final frost where you live and begin your growing season after it. Since frost dates vary across regions, your gardening time may fall anywhere within December to June.

  • For example, Boston in northeast US has its last frost on April 8, so residents here should plant Thuja trees on April 9.
  • Meanwhile, the weather in Flagstaff, southwestern US, won’t warm up until June 11, so the best time to plant green giant arborvitae here is about two months later than Boston.

2. In the fall, six weeks before the first frost

thuja-green-giant-OhioAside from spring, Thuja green giant planting is best done during autumn. To narrow down your gardening date, look up the first frost of your locality and count backward six weeks. The result will be the latest date for growing Thuja trees.

Usually, gardeners can plant green giants up until October or even November, provided that their first frost does not come too early.

  • For instance, Redding, California, welcomes its first frost on November 16, making planting on October 5
  • On the other hand, Cleveland, Ohio, often sees the first signs of frost on October 14, meaning the city’s Thuja green giant Ohio trees must be in the ground by September 2.

How to Plant Green Giant Arborvitae Tree


It’s best to grow green giants from cuttings, as seeds will not produce plants identical to their parents. So, purchase a Thuja tree transplant and keep in mind the tips below.

1. Select your planting site

Pick a location with at least six hours of sunlight per day, and avoid planting near roads so that salt won’t kill or brown arborvitae leaves. In fact, Thuja trees need to be 6 feet away from roads and buildings.

As for the planting medium, Thuja green giants can grow in clay soil and loamy soil, though the latter is preferable.

Adequate drainage is also essential, and soil with this attribute will release water from a 12×12-inch hole within 10 minutes.

2. Plant the arborvitae tree

Remove detritus from the ground and dig a hole more extensive than the pot carrying the transplant. Mix compost into the soil to supply nutrients such as nitrogen, but refrain from adding it if the ground is somewhat fertile already.

Then, thoroughly soak the Thuja roots and pull the plant from the nursery container. Set it into the hole you made while making sure the roots spread in all directions. Take note of how the Thuja sat in its container and mimic its planting depth here; do not bury the arborvitae too deeply into the ground.

If you’re growing several trees at once, Thuja green giant spacing is 5 feet apart in straight rows and 8 feet apart in staggered rows. As for the distance between hedges, 4 feet will do.

Once you’ve positioned the plant, fill the hole with soil, but stop mid-way through the process to irrigate it.

Afterward the water has completely drained, put the rest of the soil into the dug area and press it lightly to eliminate air pockets.

3. Care for the Thuja tree

Spread three inches of mulch around the tree, but avoid the trunk while you do this. Water immediately after planting so that the soil is wet but not soggy.

In practice, irrigation should be frequent within the first three months, at least once every two days or daily if necessary. After this period, an inch of moisture per week should suffice to help Thuja plants grow fast.

As for fertilizing, green giants should not be fertilized until their second year, when the tree roots are strong enough to handle it. Even then, go for a slow-release formula and apply it once in spring and fall only.



Can you plant Thuja in winter?

For Thuja plants to survive winter, you must grow them before the first frost, as described above. Having established roots will allow these trees to go dormant during the cold season and continue developing once spring comes.

Can I plant Thuja in summer?

You can certainly try, and there’s a chance you may succeed as well, but summer is not ideal for growing Thuja trees. The season’s high heat results in dry soil and low humidity, both of which can kill your arborvitae.

Plus, transplanting Thuja is near impossible during this time, at least from my experience. If you cannot wait until fall, pick late summer as your gardening time and shade the tree from extreme heat.

How long does it take for a Thuja green giant to become established?

Usually, Thuja green giants will take three years to establish themselves. During the first two years of planting, their branches need more protection against winter weather so that they don’t break.

In practice, you should tie Thuja offshoots with bands of Hessian fabric or old T-shirts. Use one band every two feet, and limit this practice to freezes in the double digits only.

Covering the tree all the time will create problems like blocking sunlight and hindering growth.

How far from a fence should I plant a Thuja green giant?

How far apart should a Thuja be from the fence?

For a 5-year-old Thuja green giant, six feet from the fence will do. However, the tree will need at least 10 feet of horizontal space once it reaches ten years of age. As for mature green giants, 15 or even 25 feet is best.

What is the growth rate of Thuja green giants?

In ideal circumstances, these plants will grow three to five feet annually, though two to three feet are more common. Check out the growth chart below for estimates of how tall Thuja trees can get at different stages:

Age Height
5 years 10 feet
10 years 20 feet
15 years 30 feet
20 years 40 feet

How much does a Thuja green giant cost?

Before buying your transplant, consider how old you want it to be. Generally, taller or more mature trees will have higher prices.

For instance, a 1-2 feet Thuja plant will cost around $20 only, while a 6-feet one will set you back $200.

On an even more extreme end, a 12 foot green giant arborvitae price is approximately $1,500, including labor cost.


When to plant Thuja green giant? Hopefully, this article gave you the answer to that question, along with tips on how to grow arborvitae trees well. In short, while you can theoretically grow the plant when there’s no frost, spring and fall would be the best occasions.

Should you still have questions on this topic, we’ll be glad to answer them. Until then, have fun gardening!

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