How to Grow Techny's Emerald Arborvitae
Techny's Emerald Arborvitae
Thuja occidentalis 'Techny'
shrubTechny's Emerald is a narrow, columnar evergreen shrub prized for its dense, vibrant green foliage that maintains its color even in harsh winters. This cultivar is exceptionally cold-hardy and compact, making it ideal for hedges, windbreaks, and formal landscaping where space is limited. It retains its rich emerald color year-round without the winter bronzing common to many arborvitae varieties.
When should you plant Techny's Emerald Arborvitae in your zone?
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Example Techny's Emerald Arborvitae timeline · Pittsburgh, PA (Zone 6b)
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Plant Techny's Emerald Arborvitae
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Techny's Emerald Arborvitae
Late summer into fallBefore the first fall frost (≈ Nov 8)
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Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-8, exceptionally hardy in cold climates
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Get my Techny's Emerald Arborvitae timeline →Growth Stages
Establishment
First 1-2 yearsNewly planted sapling with developing root system; foliage bright green but may show slight transplant stress.
Water consistently and mulch with 2-3 inches of wood chips. Avoid heavy pruning. Stake if needed in windy locations.
Young Growth
Years 2-5Plant extends upward and fills out laterally; foliage becomes denser and darker green.
Maintain consistent moisture. Light shaping of outer edges to encourage dense branching. Remove any dead or damaged branches.
Developing Structure
Years 5-10Plant reaches 50-75% of mature height; columnar form becomes clearly defined.
Prune lightly in spring to maintain shape and density. Avoid heavy pruning into old wood. Continue regular watering during drought.
Mature
Year 10 onwardPlant reaches full height (15-20 feet) with full, dense emerald foliage; established deep root system.
Minimal pruning needed; light touch-ups in spring only. Monitor for spider mites in hot, dry conditions.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with horticultural oil or insecticidal soap in dry, hot conditions. Increase humidity by misting. Avoid excessive nitrogen fertilizer.
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Hand-pick and destroy bags in fall/winter. Apply Bacillus thuringiensis (Bt) in spring when larvae are active.
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Remove and destroy infested foliage. Apply neem oil in spring. Generally causes minimal damage.
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Prune out affected shoots. Apply dormant oil in late fall or early spring.
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Spray with horticultural oil in dormant season or during active growth. Moderate infestations usually don't require intervention.
Uses
Hedges and Windbreaks
HouseholdTechny's Emerald's narrow, columnar form and dense foliage make it ideal for creating privacy screens, living fences, and windbreaks in cold climates. A single row or double-staggered rows provide excellent wind and noise protection. [source]
Formal Landscaping & Ornamental Use
HouseholdThe consistent emerald green color, narrow upright silhouette, and minimal branching below create a sophisticated formal appearance suitable for contemporary landscapes, entrance plantings, and specimen displays. [source]
Fresh Greenery for Arrangements
CraftSoft, feathery branches are popular in holiday wreaths, garlands, fresh flower arrangements, and holiday decorations, maintaining their color and fragrance for weeks when cut. [source]
Shelter for Birds and Small Animals
WildlifeDense foliage provides excellent year-round shelter, nesting sites, and cover for birds, small mammals, and beneficial insects, supporting biodiversity in gardens and landscapes. [source]
Traditional Herbal Uses
MedicinalArborvitae foliage has been used in traditional herbalism and some cultures for respiratory support, though modern scientific evidence is limited. Contains volatile oils and compounds historically valued in folk medicine. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Not harvested in the culinary sense. Foliage can be cut for fresh greenery arrangements year-round. Cut branches in late fall through early spring for longest vase life. Make cuts just above a lateral branch to maintain plant shape.
Fun Facts
- 🌱 Techny's Emerald was developed in Schaumburg, Illinois, and is sometimes called 'Techny' because it was originally selected at a technical college (now Harper College). It was specifically bred for superior cold hardiness and winter color retention.
- 🌱 Unlike many arborvitae cultivars that turn bronze or olive in winter, Techny's Emerald maintains its vibrant emerald-green color year-round, even in zones 2-3 winters, making it among the best cold-hardy, color-retaining arborvitaes available.
- 🌱 The name 'arborvitae' comes from Latin meaning 'tree of life,' and this species was one of the first North American plants introduced to European gardens in the 1500s, highly prized for its aromatic wood and medicinal properties.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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