How Often To Water Emerald Green Arborvitae?

Emerald Green Arborvitae (Thuja occidentalis), or the Northern White Cedar, is an evergreen widely used as an ornamental addition to the landscape. Emerald Green Arborvitae can add an accent to your garden or make up a living privacy fence.  If you've just planted some of these green beauties or are thinking about it, you probably have questions about their care. You're in the right place. This article will use our combined research to lay out detailed watering requirements for your Emerald Green and some tips on keeping your tree healthy.

A newly planted Emerald Green Arborvitae needs to be watered thoroughly every 3-4 days. Once your Arborvitae is established, it will require 1 inch of water once a week. How much water to be given depends on the size of your tree. 

As you can see, the water requirements change depending on the life stage of your tree. Read on as we discuss these watering needs in more detail and explain what it looks like if your Emerald Green Arborvitae gets too much water. 

A gardener is planting a small sapling Thuja occidentalis Emerald Green, Smaragd Arborvitae from a pot into soil. How Often To Water Emerald Green Arborvitae?

Watering Your Emerald Green Arborvitae

Emerald Green Arborvitae is a hardy tree. This tree thrives in moist soils that are neutral or alkaline and is low maintenance when it comes to care. The right amount of water and pruning are the crucial elements to having a happy Emerald Green. These trees love full sun but ensure the soil around your tree is never completely dry. 

Planting Cypress, Thuja with Roots (Thuja Occidentalis Golden Brabant)

Soil that dries out around a newly planted tree can cause leaf drop and causes overall stress to your Arborvitae. A stressed-out tree is susceptible to disease, pests, and fungal take-overs. As your Arborvitae works towards becoming an established tree, it is essential to water thoroughly and deeply in the recommended time frame. This consistent watering is what encourages the tree roots to grow deep and your tree to live happily. Let's talk more about how much water your tree should be getting. 

Read more on our blog post, “Do Arborvitae Have Invasive Roots?

How Many Gallons Of Water Does An Arborvitae Need?

You know how often your tree needs to be watered, but how much water should you be giving? A good rule of thumb for watering your Arborvitae is to provide 10 gallons (ca. 38 liters) of water per 1 inch (ca. 25 mm) of trunk diameter.  

thuja brabant thuja occidentalis thuja plicata arborvitae ball close up.

Newly planted Emerald Green Arborvitae require more supplemental water irrigation versus established trees. If you live in a rainy part of the world, the water requirements for an established tree are typically taken care of by nature. On the other hand, if the climate is dry and hot, it is crucial to look out for signs of dehydration in your tree. 

Looking to get creative with your watering system? The video below showcases a DIY simple irrigation system:

How Do You Know If Your Arborvitae Is Under Watered?

With a newly planted Emerald Green Arborvitae, you want to ensure the soil is always moist.  When checking the soil, if the top few inches are dry, it is time to add more water. You may be tempted to stop watering your Arborvitae in the fall. Don't do this. Continue checking your tree and watering through fall and even in winter if the season is mild and unusually warm. You do not want your tree to dry up in winter from lack of moisture. 

Closeup of green thuja occidentalis. Fresh green leaves, branches of thuja trees close up. Thuya twig occidentalis, evergreen coniferous tree. Chinese thuja. Conifer cedar thuja leaf green texture.

When it comes to established Arborvitae, they will show signs of dehydration that include needle drop or color change. You may see the branches or needles turning a yellow or brown color, then falling off. Arborvitae can have delayed reactions. Seeing these symptoms may mean the tree has been without water or stressed for some time. This is why checking the soil regularly is important. 

Read more on our blog post, “How Big Do Arborvitae Get? [By Type]”

Can You Overwater An Emerald Green Arborvitae?

You know the troubles of underwatering, and yes, overwatering is just as big of a concern. There are just a few staples in Arborvitae care, and getting the watering just right is one of them. Too much water or poor soil drainage can cause a lot of damage to your Emerald Green Arborvitae. 

Watering young thuja plant by watering can

If your tree is soaking in an abundance of water, it is at risk for root rot. When Arborvitae get root rot, you will see discoloration of the foliage and the death of branches. The roots will become discolored as well and eventually start to break off. 

Garden shop. A row of thuja and juniper in pots offered for sale.

Roots dying off are a big issue for your tree. This rotting process poses other problems as well. Rot makes your tree more susceptible to fungal or bacterial infections and other pests that want to feed on your tree. You want to catch overwatering as early as possible to avoid this state. Let's discuss what to look for. 

Read more on our blog post, “Arborvitae Tree Going Brown And Dying — What To Do?”

How Do You Know If Your Arborvitae Is Overwatered?

When we start to see discolored branches and needles and note dieback, your tree has been overwatered for some time. Are there ways to catch this mistake earlier to avoid disease and death of the tree? Sure there are. 

dry with green cypress foliage symbolize life and death background

After you plant an Arborvitae, check the soil consistently. If you notice puddles around the tree or the soil is always wet, your tree is getting too much water. The soil should maintain a moist state but not be wet. The placement of your tree can impact this as well. If your Emerald Green Arborvitae is planted downhill or not deep enough, this can increase the chance of water piling up during particularly wet seasons. Keep an eye out for this, as you may need to add a drainage system to avoid issues. 

Death of an Emerald Green Arborvitae Tree as it turns brown, Thanks to the family Dog urinating on it daily, is an unfortunate outcome o a beautifully landscaped lush green yard.

Did you know the time at which you water your trees can impact them? Watering too close to the dark can put your tree at risk of getting too much water. With the lack of sun and colder temperatures, a wet tree can't dry as quickly, and being wet for too long can lead to root rot.  

A dry branch of a thuja in a garden that has been damaged or ill.

In cases of too much water, you need to assess why this is happening and correct it. This can mean adding a drainage system, adding soil with better drainage, or other environmental controls. You may also have to treat underlying issues if root rot and other conditions are present. 

Read more on our blog post, “How Long Do Arborvitae Live? [By Type]”

How Do You Keep Arborvitae Healthy?

Arborvitae planted in the wall of a mansion, How Often To Water Emerald Green Arborvitae?

You are well-informed on the watering needs of Arborvitae, but what else does it take to keep these evergreens happy and green all year round? Not too much, actually. These trees are hardy and can survive some episodes of stress, but why put them through it? Here are some guidelines on keeping your Arborvitae healthy and happy. 

Sun or Shade

Emerald Green Arborvitae can survive in partial shade, but they love full sun. The healthiest Arborvitae gets about six hours of direct sunlight per day. Full shade is a no-go, as this will decrease the density of your tree. 


You can test your soil often for nutrients, minerals, and pH levels. Arborvitae trees are adaptable to their environment, but they do have preferences. These trees are happiest in well-drained loamy soils with a pH level of 6-8. 


Pruning can be a fun-shaping event that will give a unique spark to your garden. This process also promotes denser growth and thicker needles and branches. To get a filled-out appearance, prune your Emerald Greens in early spring. 


Arborvitae can go without fertilizer, but it can be utilized if you want to boost growth or you notice stunted growth. Arborvitae like slow-release and nutrient-rich fertilizer options. 

Have a look at this short video on planting and caring for an Emerald Green Arborvitae:

Learn more on our blog post, “Should You Fertilize Arborvitae?”

Concluding Thoughts

A gardener is planting a small sapling Thuja occidentalis Emerald Green, Smaragd Arborvitae from a pot into soil. How Often To Water Emerald Green Arborvitae?

Newly planted Emerald Green Arborvitae need watering about twice per week. Established Arborvitae need watering only per week. Keep in mind the amount of water your tree naturally gets from rain, so you don't overwater. Now you know that both under and overwatering can put your tree at risk for some serious issues.

Luckily, there is plenty of information here to ensure you are getting the right amount of water to your tree and some signs to check for that would indicate otherwise. We hope you found this article helpful. Happy planting! 

Have questions about Winter care for your Arborvitae? Have a look at our blog post, “Should You Wrap Arborvitae For Winter?”

One comment

  1. Yeah I think the approach above may be overkill on the watering. I planted 40 emerald greens a year ago as 1 foot tall plants in the autumn in Zone 7a, in heavy clay based soil. Watered roughly weekly, using a moisture meter to keep soil at moderate – low moistness, for roughly 3 months. Once winter hit I stopped all watering and really didn’t water again for the remainder of the year, including through summer, relying on snow melt and regular rain. I have lost zero plants in the last year and they’re all thriving, having grown about half a foot since then and looking very healthy. The concept of over underwater is too nebulous without a water gauge. Buy one, they are cheap and anything above bone dry is generally sufficient moistness for young plants, in my experience.

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