Description & Overview

Techny Arborvitae is a broad-based, pyramidal evergreen with dense, rich green sprays of foliage that hold its color through winter. This medium-sized conifer can grow beyond the oft-stated max of 10′ to 15′ reaching upwards of 30′ feet and 10 to 15 feet wide. With a chunky form, Techny is a nice choice for privacy screening, blocking objects, or delineating a property line. It has a much more open habit compared to Emerald Arborvitae (Thuja occidentalis ‘Smaragd’) but thickens up with age. Techny is a cultivated variety of Thuja occidentalis, the native Wisconsin Northern White Cedar.

Core Characteristics

Category: Conifer

Wisconsin Native: No - Variety of North American Native

USDA Hardiness Zone: to zone 3

Mature Height: 25-30 feet

Mature Spread: 10-15 feet

Growth Rate: Moderate

Growth Form: Pyramidal, broad

Light Requirements: Full Sun

Site Requirements: Average, well-drained

Flower: N/A

Bloom Period: N/A

Foliage: Green

Fall Color: None

Urban Approved: Yes

Fruit Notes: Small, light-brown seed cones

Suggested Uses

For the best growth, Techny Arborvitae should be planted in full sun in well-draining soils. Although it will tolerate part shade, growth will be dramatically diminished and the foliage will become less dense. Heavy clay soils are not detrimental but light and loamy soil allows the roots to spread and take up plenty of nutrients and water. Arborvitae prefers soils that are neutral to alkaline-perfect for southeastern Wisconsin.

With foliage that extends down to the ground, Techny is very useful as a privacy screen or planted in a row to delineate a property or block winds. Ensure maximum health and longevity by spacing them to allow adequate air circulation between trees.

Dense foliage and wider form make Techny a good choice to block unsightly structures or power boxes. Just be sure to avoid planting underneath power lines.

Techny also makes a terrific backdrop to other shrubs, trees, and perennials with their dark green color and soft foliage.

Wildlife Value

A cultivar of the Wisconsin native Northern White Cedar, Techny Arborvitae supports quite a few creatures. While it may not be as beneficial as the native, it does have its merits.

Deer, Snowshoe Hares, and porcupines will heavily browse the foliage, which you may or may not want. If your goal is to feed wildlife, this is a great option. If it’s not, well, there are less palatable choices such as a Star Power Juniper.

Carpenter ants are an associated ‘pest’ for Arborvitae but attract insectivorous birds such as Pileated Woodpeckers, Downy Woodpeckers, Hairy Woodpeckers, Red-bellied Woodpeckers, Golden-crowned Kinglets, Blackburnian Warblers, Ovenbirds, Northern Parulas, Yellow-bellied Flycatchers, Winter Wrens, and White-throated Sparrows who enjoy ants as a snack. Supporting our declining songbird population is a good thing!

Arborvitae in general is a host plant for many different insects including the Arborvitae Leafminer moth (Argyresthia thuiella), Brown Angle Shades (Phlogophora periculosa), Chain-dotted Geometer (Cingilia catenaria), Curved-lined Angle (Digrammia continuata), Evergreen Bagworm moth (Thyridopteryx ephemeraeformis), Juniper Geometer (Patalene olyzonaria), Large Maple Spanworm moth (Prochoerodes lineola), Pale Beauty (Campaea perlata), Pine Measuringworm moth (Hypagyrtis piniata), Cranberry Spanworm moth (Ematurga amitaria), the Joker (Feralia jocosa), and the Variegated Midget (Elaphria versicolor).

The dense foliage provides birds and other animals with cover, habitat, and nesting locations.

Maintenance Tips

Techny Arborvitae is easy to grow and low-maintenance. Thuja occidentalis are tolerant of drought once they are established. It is important to deeply water newly planted Arborvitae to help the roots anchor and stay healthy. Adding mulch around the base of your planting will reduce plant stress and retain soil moisture.

Techny has multiple leaders and may experience damage to the top of the tree in times of heavy ice and snow. If this were to happen, one of the other leaders will take over and all will be well.

Arborvitae handles pruning and shearing like a champ, but pruning is typically not necessary as they hold their shape well. In those instances where pruning is a must, only trim back the new growth of the current season and remove dieback. Any shearing should be done in early spring before the first flush of new growth.

You shouldn’t need to fertilize your tree, but you can do so before new growth pushes in spring.

Contrary to popular belief, wrapping evergreens in winter is not needed and can hold ice and snow against the needles far longer, causing winter burn and damage. Techny Arborvitae is hardy and cold-tolerant to Zone 3 (most of Wisconsin is Zone 5).

Pests/Problems

Black Walnut Tolerant: No
Deer Resistant: No
Rabbit Resistant: No

Deer love to eat Arborvitae and the soft needles are like candy to our leggy friends. If you have heavy deer pressure in your area you may want to go with a less palatable option such as a spikier juniper. If you’ve only an occasional snackortunist, you can either accept the nibbling or try using deer fencing or deterrent sprays like Bobbex.

Ensuring your trees are not stressed (proper siting and water application) is also important so the plant has the strength to combat being browsed upon. Note that flooding or higher-than-normal water levels will reduce growth and may eventually kill trees.

Techny Arborvitae has few issues with pests or diseases. Bagworm larvae may sometimes happen, but they can be difficult to spot until they’ve already formed their bags and begun chewing. Inspect your trees in the fall when eggs are laid, and again in May through June when they hatch. The least damaging removal method is hand-picking or cutting the bags from the plants. If this is too difficult (and gross), contact an arborist for assistance.

Spider mites are the other pest that can afflict Arborvitae. They are incredibly tiny and tough to see with the naked eye. An indicator that there is a problem is that foliage begins to turn a dull green. Mites are difficult to treat and require multiple applications of a targeted product to avoid harming beneficial insects. We recommend contacting an arborist for assistance.

The best prevention is appropriate care. Make sure your Arborvitae are watered properly and a mulch ring is applied around the base of the tree to help reduce moisture loss and protect the roots in winter.

Leaf Lore

The genus name Thuja is Greek for “a kind of juniper,” while the specific epithet occidentalis means “from the Western (Occidental) world.” Techny originated as a seedling selected in the 1960s at Mission Gardens in Techny, Illinois, and is the origin of the cultivar name.

The mother plant, Northern White Cedar (Thuja occidentalis) reaches ages over 800 years!

Thuja occidentalis in general was used by several Indigenous tribes for many purposes. Arborvitae foliage is rich in vitamin C and was used to treat scurvy. All parts of Northern White Cedar as a cough syrup, a deodorant, a disinfectant to fumigate for smallpox, to treat headaches, and as a smudge to revive unconscious people. Wood was made into canoe ribs, fishing spears, and toboggans, and bark was used for weaving bags.

Leaves have been used in steam baths to treat rheumatism, arthritis, and colds.

Companion Plants

Adding biodiversity to your privacy or green screen is important to avoid a mass wipeout (think ash trees) and will add lovely texture and color. Combine Emerald Arborvitae with Taylor Juniper, Mountbatten Juniper, Eastern Red Cedar, Iowa Juniper, Burkii Juniper, Star Power Juniper, Cypress Spruce, White Spruce, Norway Spruce, White Pine, Degroot’s Spire Arborvitae, Holmstrup Arborvitae, Pyramidal Arborvitae, Wintergreen Arborvitae, or Green Giant Arborvitae.

Use Techny Arborvitae as a backdrop to colorful plants such as Redosier Dogwood, Royal Raindrops Crabapple, Glossy Black Chokeberry, Dwarf Bush Honeysuckle, St. John’s Wort, Center Glow Ninebark, American Filbert, or Winterberry.

Techny Arborvitae is a broad-based, pyramidal evergreen with dense, rich green sprays of foliage that hold its color through winter. This medium-sized…
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Written by Beth DeLain