Green Giant Arborvitae Growth Rate

Green Giant Arborvitaes can grow up to 50 feet. How fast do they grow and how can you maximize their growth rate?

Hedges and plant screens are often more aesthetically pleasing, more durable, and less expensive than fences. However, shrubs do take some time to grow. Therefore, if growing a hedge or privacy screen, you want to choose a plant that grows very quickly. The ‘Green Giant’ arborvitae is a great choice.

‘Green Giant’ arborvitae has a huge, robust, and quick-growing shape that ranges from pyramidal to canonical. It has thick, deep green foliage that becomes a little darker or bronze in the winter.

So just how fast will this tree grow? In this article, I will discuss the growth rate of this magnificent shrub and how to quicken its development.

How Fast Do They Grow?

 ‘Green Giant’ arborvitae grow at a remarkable speed. In the first few years of life, a growth rate of 3 feet per year is typical, but under the right conditions, it can grow 5 feet per year.

an array of giant arborvitae trees

Mature Size

After a period of ten years, a mature tree may have reached a height of up to 50 feet and a width of up to 5 feet.

Where Do They Grow Best?

This variety does best in USDA Hardiness Zones 5 to 7. Although it may grow in a variety of soil types, including sandy soil and clay, it does best in wet, rich, and well-drained loam. It is best to steer clear of damp soil that does not drain adequately as well as spray or salt exposure.

How Much Sun Do They Need?

‘Green Giant’ arborvitae do best in direct sunlight. They can tolerate partial shade. In regions with hot summers, they prefer a few hours in mild afternoon shade.

Tips to Optimize Growth Speed

Already a fast-growing tree, ‘Green Giant’ arborvitae have the potential to grow up to 5 feet a year with the appropriate care. Here are some suggestions that can help your ‘Green Giant’ grow more quickly.

1. Plant Appropriately

Before you begin planting your arborvitae, make sure you can provide everything they need. After you have chosen the path that your hedge will follow, begin preparing the ground.

Ideally, you should dig to a depth of 12 inches. This is the depth that a full-sized spade or the tines of a tiller reaches. 

Make sure your hedge has a width of at least 3 feet available for its development. You should regularly provide organic material, as it gets depleted over time. Mulch every spring to a depth of a few inches.

an array of giant thuja trees in the farm

2. Water Appropriately

Before planting, you should thoroughly water the root balls. Then, place the shrubs into the prepared hole and replace roughly two-thirds of the soil. Water thoroughly and then add the last layer of soil. This procedure ensures that water is present both below and above the surface of the planting hole.

Maintain a good water supply during dry times to ensure optimal growth but allow the soil to partially dry out between watering sessions. Instead of watering infrequently in small amounts, water less frequently but thoroughly. Avoid letting the soil dry out completely. Established plants are very drought-resistant, but when the soil is dry, they won’t be growing—just surviving.

3. Space the Plants Appropriately

You may be tempted to plant your shrubs closely together but doing so is a bad idea. You must give the plants sufficient space to grow and spread out sideways to form the foundation of your hedge. 

If you plant the arborvitae too closely together, there is a chance that in a few years the bottom half will become thin and open. The minimum distance between plants should be 3 feet. ‘Green Giants’ grow so quickly that they will soon fill in that space.

4. Fertilize Correctly 

Regular watering and fertilizer are crucial for your hedge’s best start. Begin using a granular fertilizer regimen after your hedge is established and apply it once in early spring and again in the middle of summer. If you are using a slow-release fertilizer, use it only once a year.

Alaine Connolly
Alaine has been working way too hard in horticulture since 1992, beautifying golf courses, resorts, and hotels. She is a part time landscape designer who works full time caring for a 28,000 square foot public garden. At home, she maintains her own 400 square feet plot. Alaine lives in northern Illinois - zone 5b.
More ArticlesTrees and Bushes