How to Plant, Grow, and Care For Arborvitae

Arborvitae is a coniferous tree or shrub in the Cyprus family. This North American native tree has quickly gained popularity as an ornamental. It is commonly used to create a living privacy screen, fence, or windbreak in the landscape. It grows in a wide range of environments throughout North America within USDA growing zones two through eight. 

This tree is adaptable to a variety of soil conditions provided that they are well-drained and that it receives full sun. It is also a long-lived perennial and can survive for anywhere between 25 and 150 years! This means it will be a long-lasting presence in your garden. 

What Are Arborvitae?

Also known as northern white-cedar, eastern white-cedar, and the shorthand slang “arbs.” Other common names include swamp cedar, American arborvitae, and eastern arborvitae. The name arborvitae is Latin for “tree of life.” They are perennial evergreen shrubs or trees in the genus Thuja that are widely used in ornamental landscaping today. 

History

French botanists brought this evergreen back to Paris in 1536, making it the first North American tree species to be brought to Europe. It was quickly adopted as an ornamental plant. Because of its rot-resistant wood, these trees were used by Native Americans to build canoes. 

Native Area

These trees are native to North America, specifically eastern Canada and north-central and northeastern United States. In Canada, its range reaches the Arctic tree line and the southern tip of the Hudson Bay. It prefers to grow in places with cooler summers and a shorter growing season. Connecticut is on the southern edge of its native range. 

Characteristics

Arborvitae are upright trees with feathery sprays of flat, dark green, scaly needles that resemble juniper foliage. The trunk has red-brown bark, and they produce seed cones that start slender and yellow-green and turn brown as they mature. It tends to grow in a pyramid-like shape which can be exaggerated through pruning. Many varieties are available, which can range in size and foliage color.

Uses

Nowadays, it is used as an ornamental. Historically, the bark and foliage has been brewed into a vitamin-C-rich tea used to treat scurvy. The rot-resistant wood is also used for fencing and log cabins.

An oil can be extracted from the boughs and is used in cleansers, soaps, and perfumes, which smells like cedar. As an ornamental in the landscape, is it used to create a living privacy fence, a windbreak, or to add a pop of evergreen color to the landscape year-round. 

Where To Buy Arborvitae

Arborvitae plants are widely available at big box stores, online retailers, and local nurseries. Searching online retailers will give you the biggest range of varieties available.

On the other hand, shopping at a local nursery will likely result in picking up a variety that is well-suited to your area, not to mention the in-person information that you can receive at a local nursery. If you have a friend growing arborvitae, then you might be able to get your hands on some cuttings. More on that later! 

Planting

The best time to plant is in early spring before they are actively growing. Planting in early spring will ensure that roots can establish before the first frost and successfully survive over winter. To plant your tree, dig a hole twice as wide as the root ball and just deep enough so that it matches the depth of its original container. Backfill with a mixture of the soil that was dug out of the planting site and compost. Water it in well. Space trees at least three to four feet apart to give them space to fill in.

How to Grow

Arborvitae are low-maintenance once established. However, they will require a moderate level of care during their first few years and regular pruning throughout their lifetime. 

Light

These perennial evergreens require full sun. This equates to six to eight hours of direct sunlight for most varieties. In scorching and dry climates, they can benefit from afternoon shade. They can survive in partial shade conditions, meaning four to six hours of direct sunlight per day, but their foliage will not be as full and dense when grown in shady conditions. 

Since this is a perennial plant, you should also consider where the sun will be during the winter when it is at its lowest point in the sky. Your plants will still require six to eight hours of sunlight per day then, too! For this reason, it is important to make sure it will not be shaded out by taller structures during the winter. 

Water

You will need to water weekly during the first year after planting. Arborvitae do not do well in overly wet soil conditions, and for this reason, they prefer a slow release of water around the root zone. This can be achieved by using a drip irrigation line or watering bag that sits in a ring around the base of the tree and slowly drips water into the soil. 

Once established, they will require ½ inch to one inch of water per week. Depending on where you live, you might receive this via precipitation and not need to provide any supplemental irrigation. A one to two-inch layer of mulch around the base of your plants will help retain moisture as well. The most important thing is to make sure that the first inch of topsoil has dried out before watering again. 

Soil

These trees prefer loamy, well-drained, neutral to slightly alkaline soil if you want to provide optimal growing conditions. However, ultimately they are not picky and can survive in a variety of soil types as long as they are well-draining.

Waterlogged or heavy clay soils can cause a wide range of growing problems for your arborvitae. Adding compost or organic matter to the soil at the planting site will help improve the drainage and soil structure. 

Temperature and Humidity

The ideal temperature range for arborvitae during the growing season is between 60-75 degrees Fahrenheit (16-24°C). They also enjoy moderate levels of humidity. They do not like to be completely dry, but overly humid conditions can cause fungal issues. Adding a layer of mulch around the base of your plants can help protect them from temperature and moisture fluctuations in both summer and winter. 

Fertilizing

Whether or not you choose to fertilize your arborvitae depends on your growing goals. If you want your tree to grow fast and fill in a hedge, you should fertilize in the spring using a nitrogen-heavy slow-release fertilizer like 10-5-5. This will give a much-needed boost just as new growth appears, and you will see an increase in foliage growth. However, keep in mind that with increased growth, you will also need to stay on top of pruning and shaping your plants, or they can quickly become unruly. 

If you want slow growth so that you can easily contain the overall size and shape with once-yearly pruning, then fertilizing is not necessary. The tree will grow slower but will be more manageable when it comes to pruning chores. This is an attractive option for gardeners who want to keep it low-maintenance. 

Maintenance

Once yearly, pruning is required to maintain the overall shape of your evergreen shrub. This is also an opportunity to remove dead or damaged branches. It is best to prune in mid-spring after new growth has begun to appear. This is because arborvitae grow on new wood. 

When pruning, it’s important to make sure not to reduce the plant by more than one third in size. Any more than this can stress, damage, and ultimately kill the plant. Use sharp pruning sheers, loppers, or an electrical saw when needed. Make sure the base of the plant stays wider than the top which will give it the overall pyramid shape that they are admired for.   

Growing In Containers

The short answer is no; arborvitae can’t be grown in pots. The long answer is yes, but only temporarily. They can be grown in pots for a few seasons until they are finally placed in the ground.

Since this tree can grow to be quite large, there is not a pot or container that will be big enough for its fully mature size. However, if you need to keep your arborvitae in a container for a few seasons while you clear an area in the landscape or otherwise prepare the planting site, then this can be done. It is not recommended to attempt to grow these trees in containers for the entirety of their lives. 

Propagation

Arborvitae can be propagated from softwood cuttings taken in November to December when the tree has gone dormant. These cuttings will readily root when placed into sand or well-drained potting mix, provided they are kept evenly moist. The branches root so easily that the branches of fallen trees will often root where they touch the ground. 

Take a cutting, remove the lower foliage, and stick the stem into the soil. In a few weeks, roots will develop. The following spring, you will have a young sapling ready to go out into the garden. 

Common Problems

Arborvitae do suffer from a few common growing problems. Luckily, with their increase in popularity, there has also been an increase in information and tactics to manage these issues. 

Winter burn

This type of browning of the foliage is the most common growing problem for arborvitae. It occurs when the tree is grown in an open and unprotected area that is exposed to severe winter conditions. This is common because arborvitae are often used as a windbreak or privacy screen, which means they are often standing on their own and exposed on at least two sides.

Foliage facing south or west is most often affected because foliage that is facing the sun will begin to transpire or lose moisture through the leaves. This moisture loss, combined with severe winter weather, results in browning foliage at the tips of the branches. 

This is compounded by the fact that during extremely cold weather, the ground is frozen, and plant roots can’t take up water to replace what has been lost from the foliage. As a result, it dries and browns and is unlikely to recover. Winter burn does not necessarily indicate the overall death of your tree. In the spring, you can prune back any dead, damaged, or dying foliage, and new growth should appear to replace it, providing that your tree is otherwise healthy. 

Pests

Bagworms are a potential arborvitae pest. Signs of bagworms include defoliation and the characteristic two-inch-long “bags” hanging from the tree, just like ornaments. These caterpillars live in silk bags covered with bits of foliage taken from the host plant. Large populations can strip a tree of its foliage and eventually result in plant death. Bagworm adults are most active during May through July.

Male bagworms transform into a moth that seeks out the females for mating. The females never leave their cocoon. If you notice the presence of moths around your arborvitae, then this can be another sign of a bagworm infestation. 

Scale will appear as small, brown, rounded lumps on your plant’s stems and leaves. Pop off these insects with a Q-tip dipped in alcohol. If the infestation of these brown spots has not progressed too far, then remove infected leaves to prevent their spread. 

In more serious cases, you can apply an organic insecticide such as neem oil. Conventional contact insecticides work as well. Parasitic wasps are a natural predator of scale insects and will lay their eggs on the adults. When the larvae emerge, they kill the host insect. Attract these wasps to your garden by growing a variety of umbel flowers like dill and yarrow.   

Depending on where you live, deer and mites can be considered pests as well. In their native habitat, arborvitae provide a food source year-round. Deer may munch on the bottom portion of the trees but rarely cause anything other than cosmetic damage. Mites are common pests that you don’t need to worry about if your tree is thriving.

Diseases

Diplodia tip blight is a common fungal disease that affects pines and can also affect other evergreens like fir, spruce, and juniper. The disease is most common in older trees that are under some sort of stress from drought, hail or snow damage, overshading, or compacted soils. The fungus affects current-year shoots and can be identified by the tips of new growth turning brown. If you see cankers in the crooks of branches, this disease has reached an advanced stage. 

When possible, remove infected plant material to remove the fungus from the tree. In extreme cases, you can also use fungicides to treat this blight. Since fungus loves overly wet conditions, a good preventative measure is to avoid wetting the foliage on your trees whenever possible. 

Frequently Asked Questions