Emerald Green Arborvitae Facts and Care

Sally Painter
Row of green thujas

Learning the facts about the care of Emerald Green Arborvitae ('Smaragd') can help you determine if it's an evergreen landscaping option for your home. You may be surprised to discover how easy it is to grow these lime green pyramidals.

Exploring Emerald Green Arborvitae Facts and Care

The arborvitae (Thuja occidentalis) is an evergreen that is found in shrubs and trees. The semi-dwarf Emerald Green arborvitae is noted for its narrow conical or pyramidal shape. It is often chosen for an evergreen hedge or several are planted close together for screening.

Emerald Green Description

The leaves have a glossy sheen and are bright green with flat needles. When the plant produces cones, they are a nice urn shape. The cones are no longer than ½ inch, and come fall, they turn brown.

  • Height: 7' to 15' (some species can reach 20' high)
  • Spread: 3' to 4'
  • Hardiness: Zones 2 to 7

How to Select a Healthy Plant

You will quickly recognize a healthy Emerald Green Arborvitae by its vibrant lime color. Things to look for and avoid purchasing if present are needles that shed when you run your hand over the limbs. There should be no sparse areas or dead wood. If the needles are brown, the plant may have a fungus or other disease. If you see any spider webs, it's possible the plant is infested with spider mites. Keep these things in mind when shopping for your shrub.

Picture of a well maintained garden

Sun Requirements

Emerald Green Arborvitae prefers full sunlight but can survive in partial shade. At the minimum plant these shrubberies where they'll receive six hours of full sunlight.

Cool and Dry Environments Preferred

This plant can survive in very cold climates as well as dry climates. If you attempt to plant in southern environments with high humidity, the shrub may suffer from a fungal disease.

Best Time to Plant

As with most plants, the fall season is the ideal time to plant Emerald Green Arborvitae. This is a fast-growing shrub/tree and will gain between 1' to 2' each year until it reaches maturity.

  • Since Emerald Green has a wide spread, leave approximately 3' to 4' between plantings when creating a thick hedge or as a privacy screen.
  • Fill the hole with loose soil and pack lightly around the plant so the roots can breathe.
  • Until the root system is established, continue to water 2-3 times a week.

Soil and Fertilizer Requirements

You want to plant Emerald Green in a location where the soil drains well. Loam soils are best. The pH should be between 6 and 8. Make sure the root ball is just a little above the ground, about 1 to 2 inches.

Keep Soil Moist

When you first plant Emerald Green arborvitae, you need to keep the soil moist. Water when the top one inch of soil becomes dry. A good rule of thumb is to water once or twice a week for the first year. This plant is drought resistant and doesn't have wet feet, so don't over water.

Fertilizer and Compost

Your best choice is to add a layer of compost around the Emerald Green as soon as you plant it. You'll want to add compost each year. You don't really need to fertilize this plant, but if it shows signs of stress with stunted growth that first year or the soil isn't built up, you can use a balance fertilizer very sparingly or opt for a slow time-release fertilizer.

Pruning Requirements

You can do early spring pruning, but only very light pruning. Never trim the bare wood, only the leaves. You do need to prune out any dead branches. This species doesn't require much pruning for it to retain its pyramidal shape, but it if needs a little help, break out your pruners. If you wish to create a hedge look, you'll need to cut out the tops and keep it pruned to conform to the hedge shape.

Corner of garden with arborvitae hedge

Diseases and Pests

The good news is Arborvitaes don't have many enemies in the insect world. The same is true when it comes to diseases. Occasionally, an Emerald Green can contract a blight in its needles and twigs. Blight is the result of poor air circulation. Prune this back, removing the disease areas. You can treat with a fungicide if needed.

Spider Mites

Spider mites can quickly infest an arborvitae and go unnoticed until it's too late. You can take preventative measures by using an organic mycorrhizae that's very beneficial for the plant.

Mealy Bugs

Occasionally mealy bugs turn up. You can treat these intruders with parasite wasps or a more aggressive treatment by creating a spray using 10-25% rubbing alcohol (isopropyl) with water. Apply once a week until there's no more infestation.

Bagworms Treatments

Another pest is the bagworm. These nasty critters can plague an arborvitae. The best remedy is to handpick the egg bags and burn them before they hatch.

Tips for Growing Emerald Green Arborvitae

A few helpful tips can make your Emerald Green Arborvitae more enjoyable. For example, if you're seeking a great topiary plant, select the Emerald Green Arborvitae for creating spiral topiaries

  • Branches can break under the weight of snow. Keep snow off the plant as much as possible.
  • Prune limbs that become broken during winter snows.
  • Make sure your plant has ample sunlight or it will grow leggy.

Growing Emerald Green Arborvitae Made Easy

For anyone living in hardiness zones 2 through 7, you can understand how easy it is to grow Emerald Green Arborvitae. In fact, you may be wondering why you haven't included this plant in your garden plans.

Emerald Green Arborvitae Facts and Care