Techny Arborvitae (Thuja occidentalis ‘Techny’) is a popular cultivar of the Eastern Arborvitae, classified botanically under the Cupressaceae family and the species Thuja occidentalis. It is a cultivated variety selected for its hardiness, dense foliage, and excellent winter color retention. Like other members of its species, it is a cold-hardy conifer native to North America, particularly suited to northern climates and demanding growing conditions.
This tree is also known as Mission Arborvitae, a name that originates from the location where it was first propagated—Techny, Illinois, by missionaries in the early 1900s. Since then, it has earned a reputation as one of the most reliable and durable arborvitaes for northern regions, valued for both its ornamental appearance and practical utility in the landscape.
Techny Arborvitae is easily identified by its broad, pyramidal shape, rich dark green foliage, and dense, symmetrical growth. The flattened sprays of foliage remain vibrant even in winter, resisting the bronzing that often affects other arborvitae cultivars in cold climates. The bark is fibrous and reddish-brown, and small, upright cones appear seasonally. Its dense form and consistent growth habit make it ideal for hedges and screens without needing frequent pruning.
This cultivar grows at a moderate rate, typically 12 to 18 inches per year, and can reach a mature height of 15 to 20 feet with a spread of 6 to 10 feet. It is slower-growing than fast-spreading cultivars like Green Giant but offers a more compact, manageable size and form. With proper care, Techny Arborvitae can live for 40 to 70 years or more, making it a long-term investment in residential or commercial landscapes.
In terms of distribution, Techny is widely planted throughout the northern and central United States and southern Canada, especially in areas with cold winters and short growing seasons. It adapts well to a variety of soil types, including clay and loam, as long as the soil is well-drained. While it prefers full sun, it will tolerate light shade, although dense shade may lead to sparse growth.
Techny Arborvitae thrives in USDA Hardiness Zones 3 through 7, giving it excellent adaptability in regions with cold winters and cool to moderate summers. It is less suited to southern zones with prolonged heat and humidity, where it may struggle to maintain its vigor and density.
Other notable facts about Techny Arborvitae include its low maintenance requirements, strong resistance to winter damage, and excellent response to pruning if shaping is desired. While not deer-proof, it is somewhat less palatable than some other arborvitae varieties. Its dense growth provides excellent cover for birds and small wildlife, enhancing its ecological value.
Landscape uses of Techny Arborvitae include:
- Privacy screens and living fences
- Windbreaks in rural or exposed areas
- Formal hedges and structured borders
- Noise barriers along roads or property lines
- Specimen planting in larger yards or public spaces
- Evergreen backdrops for mixed shrub beds
- Wildlife-friendly gardens as shelter and nesting sites
- Visual buffering of unsightly structures or boundaries
Common problems associated with growing Techny Arborvitae (Thuja occidentalis ‘Techny’)
Deer browsing
– Highly attractive to deer, especially in winter
– Can cause severe lower branch defoliation and stunted growth
Winter burn
– Foliage may dry out or turn brown due to harsh winter winds and sun exposure
– More common in exposed, windy locations
Drought stress
– Shallow root system makes it vulnerable to dry conditions
– Inner foliage may turn brown and shed if not watered during droughts
Root rot
– Caused by poor drainage or overly wet soil
– Leads to yellowing, wilting, and decline in overall vigor
Pest infestations
– Can be affected by bagworms, spider mites, and leafminers
– Symptoms include browning tips, webbing, or small chewing holes
Fungal diseases
– Susceptible to tip blight and cankers in humid or crowded conditions
– Often begins with browning at the branch tips
Improper pruning
– Cutting into old wood can leave permanent bare spots
– Over-pruning can damage the natural shape and density
Snow and ice damage
– Heavy snow or ice accumulation may cause bending or breakage of branches
– Can lead to long-term deformities if branches do not recover
Poor air circulation
– Planting too closely limits airflow, promoting fungal issues
– Also increases the risk of uneven light distribution and interior browning
Transplant shock
– Newly planted trees may suffer from wilting, yellowing, or stunted growth
– Usually caused by improper planting or insufficient watering
Cultivation of Techny Arborvitae (Thuja occidentalis ‘Techny’)
Site Selection
– Choose a site with full sun to partial shade.
– Full sun ensures dense foliage and optimal growth.
– Avoid areas that are overly shaded, as Techny can become sparse and leggy without enough light.
Soil Requirements
– Techny Arborvitae thrives in moist, well-drained soils.
– Tolerates a range of soil types including clay, loam, or sandy soils.
– Prefers neutral to slightly alkaline pH but is adaptable overall.
Watering Practices
– Requires regular watering during the first 1–2 years after planting.
– Once established, it is moderately drought-tolerant but still benefits from deep watering during dry periods.
– Avoid overwatering or planting in soggy soils to prevent root rot.
Planting Time
– Best planted in early spring or early fall.
– These seasons allow roots to establish before extreme heat or cold.
– Fall planting is ideal in northern climates to avoid transplant shock.
Spacing
– Space 4 to 6 feet apart for hedging or privacy screens.
– Leave 6 to 10 feet between trees when using as individual specimens.
– Proper spacing ensures good air circulation and reduces disease risk.
Mulching
– Apply a 2–3 inch layer of mulch around the base to retain moisture and suppress weeds.
– Use organic materials like bark or wood chips.
– Keep mulch away from the trunk to avoid rot and rodent damage.
Fertilization
– Feed in early spring with a balanced, slow-release fertilizer (e.g., 10-10-10).
– Avoid excessive nitrogen which can lead to weak, leggy growth.
– Healthy soil may reduce the need for annual feeding after establishment.
Pruning and Maintenance
– Requires minimal pruning due to its naturally uniform, pyramidal shape.
– Prune in late winter or early spring to remove dead or damaged branches.
– Avoid cutting into old wood as Techny does not regenerate from it.
Winter Care
– Well-suited to cold climates, but young trees may benefit from burlap wrapping in exposed areas.
– Water deeply in late fall to prevent winter dehydration.
– Techny holds its color well through winter, unlike many arborvitae.
Pest and Disease Monitoring
– Check regularly for spider mites, bagworms, and leafminers.
– Remove bags manually or treat infestations early with horticultural oil or insecticidal soap.
– Avoid wet foliage by watering at the base to prevent fungal diseases.
Protection from Snow and Ice
– In heavy snow zones, gently brush off snow accumulation to prevent branch damage.
– Avoid planting in locations where ice frequently accumulates.
– Strong branch structure makes Techny more resilient than some other arborvitae.
Deer Protection
– Techny is not deer-resistant and may need protection in high-deer areas.
– Use deer fencing, netting, or repellent sprays especially in winter when browsing is most common.
– Repeated damage can disfigure the tree permanently.
Landscape Integration
– Ideal for hedges, privacy screens, windbreaks, and formal rows.
– Can be used as a backdrop for perennials or flowering shrubs.
– Works well in foundation plantings, urban landscapes, or rural shelterbelts due to its durability.