How to Grow and Care for Emerald Green Arborvitae

Emerald green arborvitae trees alongside brick pathway and white and blue building

The Spruce / Evgeniya Vlasova

Arborvitae are evergreen trees that are easy to care for, have year-round visual interest, and are perfect for hedges, accent trees, or a green privacy wall. Arborvitae come from the Thuga genus, and 'Emerald Green' is one of the more popular arborvitae cultivars. They grow fast up to 20 feet tall. They can withstand cold temperatures and rarely have problems with pests and diseases.

Emerald green arborvitae are best planted in the fall when they will experience minimal heat stress. Their foliage consists of flat sprays of glossy bright green needles, plus urn-shaped cones about an inch long that turn reddish-brown in the fall. Occasionally, this plant is pruned to form spiral topiaries. The tree is toxic to humans and animals.

Defining Arborvitae

Arborvitae are trees in the cypress family that are often used for hedges. All arborvitae are types ofThuja, and there are two major types. Thuja occidentalis or eastern arborvitae are native to the eastern U.S. and are the most common; however, a significant shortcoming is deer will eat them. Western arborvitae (Thuja plicata) is native to the western U.S. The western type is bigger and grows more quickly. They are deer resistant but are not as cold-hardy.

Common Name Emerald green arborvitae, Smaragd arborvitae, American arborvitae, white cedar
Botanical Name Thuja occidentalis
Family Cupressaceae
Plant Type Tree
Mature Size 12–20 ft. tall, 3–10 ft. wide
Sun Exposure Full, partial
Soil Type Moist but well-drained
Soil pH Acidic, alkaline
Hardiness Zones 2–7 (USDA)
Native Area North America
Toxicity Toxic to people, toxic to pets

Watch Now: How to Grow and Care for Emerald Green Arborvitae

Emerald Green Arborvitae Care

This cultivar, sometimes also known as 'Smaragd', because the plant was originally developed in Denmark ("Smaragd" is the Danish word for "emerald"), also makes a good foundation plant and is sometimes planted singly as a landscape specimen plant.

Leave 3 to 4 feet between each tree if you are planting as a privacy fence or screen. Heavy snow can break branches, so brush them off after a storm—broken limbs should be pruned off, and the plants may need to be staked upright until they recover.

Emerald green arborvitae tree leaves closeup

The Spruce / Evgeniya Vlasova

Emerald green arborvitae tree branches in sunlight

The Spruce / Evgeniya Vlasova

Emerald green arborvitae tree tops against blue sky

The Spruce / Evgeniya Vlasova

Emerald green arborvitae tree branches with pine cones on branches

The Spruce / Evgeniya Vlasova

Emerald green arborvitae tree branch and glossy leaves closeup

The Spruce / Evgeniya Vlasova


Emerald green arborvitae should be grown in full sun or partial shade. They generally need at least six hours of sun daily, but too much direct sunlight can stress the plant and burn the foliage. However, they should not be planted in full shade either, since this can greatly reduce the density of the foliage.


Plant arborvitae in moist but well-drained soil with a neutral to alkaline pH level. These shrubs do not like to be continuously doused in water so that their roots sit in soggy soil. Instead apply a heavy layer of compost or mulch over the root zone each year. Keep to a regular watering schedule, and the mulch will help to preserve soil moisture.


Your arborvitae will need watering twice weekly for the first few months after planting, then weekly watering (about 1 inch of water) for the next year or so. Once established, make sure it gets about a half-inch of water weekly, either through rainfall or irrigation.

Temperature and Humidity

Emerald green arborvitae does better in cooler, dryer climates. In very humid conditions, fungal diseases can be a problem. To help prevent this, plant your trees at least 3 to 4 feet apart from one another in order to improve air circulation. Avoid exposed, windy locations, especially in colder climates.


Arborvitae plants normally do not need feeding. However, if new growth is very sparse or slow, an application of a balanced fertilizer containing all major nutrients is recommended. For the amount to use, follow product label instructions.

Planting Emerald Green Arborvitae

When to Plant

Plant arborvitae in the fall to avoid heat stress and give its roots time to establish before winter arrives.

Where to Plant

Plant emerald green arborvitae in moderately moist, well-drained soil in full sun or partial shade (in warmer climates, some shade is preferable). Remove weeds, grass, rocks, and debris.

How to Plant Emerald Green Arborvitae

  • Remove the burlap wrapping around the root ball or carefully pull the root ball out of the container and loosen some of the roots.
  • Plant the root ball in a hole twice as wide and as deep as the root ball. Keep the top edge of the root ball level with the surface.
  • Fill in the soil around the root ball. When you are halfway done, water thoroughly.
  • Finish filling the hole and pack it down with your hands. Water thoroughly from the surface level.
  • Add two inches of mulch to the surface. Do not allow the mulch to touch the stem.

Pruning Emerald Green Arborvitae

If desired, light pruning in the early spring can help your arborvitae remain neat and foster thicker growth. To do so, trim the leafy parts of the branch, making sure not to cut back to bare wood. Dead or diseased branches should be removed to prevent decay and improve air circulation.

In addition, you may prune your tree to maintain the natural shape of the shrub, which is wider at the bottom and tapering inward toward the top. Especially adventurous gardeners can even prune the shape to form spiral topiaries.


Arborvitae are cold-hardy but can benefit from extra winter care, especially when young. Snow and ice can cause stem breakage. Periods of drought, high wind, and plunging temperatures can cause drying out and browning. Mulch can also keep the roots insulated and retain moisture in the ground.

To preserve the stems, tie them with twine. Or, for even more protection against hungry deer, wrap it with burlap around a circle of stakes. Burlap wraps are recommended if you live in zone 2.

Common Pests and Plant Diseases

Arborvitaes are rarely troubled by insect and disease problems. Bagworms may feed on the foliage of arborvitaes. Control them by handpicking the egg bags and destroying them before the insects hatch. Spider mites can also do damage to the trees.

The plant can sometimes suffer from needle and twig blight caused by fungi, especially if air circulation is poor. To control blight, prune off all affected branches and treat them with a fungicide.

Keep an eye out for stem canker, a fairly serious fungal disease that causes lesions, sores, and sticky resin oozing from the trunk or branches. Remove the affected branches. If the trunk is affected, the tree may not survive.

Common Problems With Emerald Green Arborvitae

'Emerald Green' arborvitae are low maintenance, cold hardy, and generally have fewer problems with pests and disease.

Browning Leaves in Winter

Arborvitae are winter hardy, and 'Emerald Green' should stay green throughout the year, but they may lose a little of their vibrancy. They are susceptible to browning when the temperatures suddenly plunge or lack water in winter. Keep giving water in the winter if the soil dries out or if there is a lack of rain or snow.

Dropping Needles

Each year, arborvitae will drop their needles from the plant's interior. It may look like the entire plant is browning from the inside out. This browning is natural and expected. The needles may start to pile up along the interior stem or trunk of the plant. Clean them out to prevent rot from spreading from the decomposing pile of needles.

Loss of Foliage From Top Down

Bagworms defoliate arborvitae, usually starting at the tree top and working their way downward. These caterpillars eat leaves, create telltale "egg bags," and leave bare branches in their wake. Left alone, they can kill the plant. To remedy the situation, remove all the bags. If it's a bad infestation, you might need a pesticide. Neem oil is an organic pesticide alternative that will kill bagworm larvae.

  • Are emerald green arborvitae easy to care for?

    They are extremely easy to care for and need little to zero maintenance.

  • How fast does emerald green arborvitae grow?

    These slim trees grow at a faster rate of speed when they are young, adding 1 to 2 feet per year. As the tree matures, the growth rate will slow to about 6 inches a year until reaching full height.

  • How long can emerald green arborvitae live?

    The lifespan of emerald green arborvitae varies from 25 years up to 150 years.

  • Do emerald green arborvitae stay green in winter?

    These trees stay emerald green all year; however, in rare circumstances, like insufficient water, dramatic temperature changes, or wind or sun damage, browning may occur.

Article Sources
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  1. University of California Agriculture, and Natural Resources. “Toxic Plants (by Common Name).” N.p., n.d. Web.

  2. Plants Toxic to Dogs List, Symptoms and Treatment.” N.p., 2 Dec. 2020. Web. 

  3. Elisabeth C. Miller Library: Gardening Answers Search Results for ‘Plant Longevity.’” N.p., n.d. Web.