This article appeared in the Fall 2022 issue of This Old House Magazine. Click here to learn how to subscribe.
If your location is zone 7, I’d recommend planting ‘Emerald Green’ arborvitae trees to create your privacy hedge. Sometimes referred to as ‘Smaragd’ because of its Danish lineage, this arborvitae will take wintry weather in stride and has excellent resistance to disease and insects.
How Tall Does Emerald Green Arborvitae Grow?
You can expect an ‘Emerald Green’ arborvitae to grow into a narrow pyramid shape, about 10 to15 feet tall and 3 to 4 feet wide when mature. It can grow up to 2 feet per year, so you won’t have to wait long for your hedge to provide effective screening. It’s best to plant these trees now, in fall, or in spring to avoid stressing them in the heat.
If you want a straight hedge, you’ll need to keep the trunks aligned, so instead of digging individual holes for the trees, you’re better off making a trench and placing their trunks 3 to 4 feet apart. Use spray paint to outline a trench location about twice as wide as your trees’ root balls, then remove the grass, weeds, and stones from the area.
Tips for Planting Emerald Green Arborvitae
- Shovel the soil onto a tarp as you make the trench about 2 inches shallower than the average height of the root balls.
- Carefully place the trees in the trench, with their best sides facing your yard, then use a sharp pronged cultivator tool to tease the surface roots from each root ball.
- Mix some compost in with the soil you dug out (1 part compost to 2 parts soil), and fill in around each tree. Leave the top 2 inches of each root ball exposed, forming a soil dam around each root ball.
- The dam is temporary; its job is to hold water around the root ball as you give each plant’s roots a thorough soaking. Fill each dam with water twice, waiting till the water drains away before filling again. Then rake away the dams and cover the roots with a couple of inches of mulch.
- Continue watering your newly planted trees once a week until cold weather arrives. To encourage growth next spring, apply a slow-release 10-10-10 fertilizer. Unless you have a dog to discourage deer on your property, you’ll need to protect your arborvitaes from being eaten, especially in winter.
- Deer repellents can be effective if reapplied regularly, but some homeowners choose to erect temporary screens around their hedges until warm weather arrives and deer can eat elsewhere.