Evergreens provide structure and form to the garden and landscape throughout the year, and are especially appreciated in winter.
One of the best is Thuja occidentalis, also called Eastern white cedar or arborvitae — Latin for tree of life — a nod to the plant’s historical medicinal properties. Native throughout eastern North America, it is exceptionally hardy, performing well even in the extreme 40-below-zero temperatures of USDA Zone 3.
Plants also thrive in challenging soil conditions, from sand to heavy clay and average to wet, including those low spots that stay wet for an extended period, especially in early spring, a situation that is problematic to many landscape plants.
Arborvitae offers a wide range of sizes, colors and forms, from large upright trees to compact rounded shrubs only a few feet in diameter. Unique foliage forms broad, flat fans of overlapping scales.
Larger, upright types make great hedges, windbreaks or a backdrop to perennial gardens. The native form grows up to 40 to 60 feet tall, though a more common size in landscapes is closer to 20 to 30 feet. Foliage may take on a yellow or brassy cast in the winter months; caused by a combination of cold, sun and wind. Plants quickly recover their lush green color when the weather warms in spring.
Several selections have been developed with excellent, rich green foliage whose color holds constant year-round. Nigra or dark green American arborvitae is considered one of the best, with deep green leaves and a pyramidal form, growing 20 to 30 feet tall with a typical spread of 4 to 5 feet, though they can reach 10 feet wide.
Techny or Mission is also deep green and pyramidal in profile, slow-growing to 10 to 15 feet with a long-term potential of 25 feet.
My particular favorite is the Emerald arborvitae (Smaragd) with a wonderful velvety green color, a little brighter than Nigra and equally nice in winter. It’s a medium sized tree, topping out at around 15 feet.
For small gardens, there are some nice selections that reach just 6 to 12 feet. Degroot’s Spire is a narrow, columnar form with rich green summer foliage, and a bronzed winter color. Holmstrup is compact and dense, good for hedges and sporting bright green foliage year-round.
If you’re looking for a small plant to mingle in the perennial garden, or even use as a foundation shrub that will rarely need trimming, choose one of the dwarf forms. Woodward globe is the most commonly available, with medium green foliage and a naturally rounded shape that looks like it has been carefully pruned. Average height is 4 to 5 feet.
Because these trees are so cold hardy, smaller compact forms can be grown year-round in large, weather-safe containers on the porch or in the garden. Prized for good winter color are 3-foot selections Danica, Hetz Midget, Pygmy Globe and Mr. Bowling Ball. They are also reliable, low-maintenance plants that will not grow up and block windows.
Rheingold has golden foliage, a rounded to cone-shaped profile, and grows slowly to 4 to 5 feet tall by 3 to 4 feet wide. Sunkist’s green foliage glows with yellow brushed edges, and forms a broad pyramid shape 10 to 15 feet tall and 4 to 5 feet wide. Yellow Ribbon has a narrow, upright pyramidal form, reaching 10 feet tall and 3 feet wide. New growth is yellow-orange, maturing to green, and takes on bronze tones in winter.
Use arborvitae to enliven the garden year-round.