arborvitae Archives - Nature Center at Greenburgh

Arborvitae gets no respect.

Though Arborvitae (Thuja occidentalis) may be the most-planted tree in suburban America, it has been given a diminished role unworthy of this majestic native tree. Planted by the thousands along property lines by developers, builders, and landscapers, rows of crowded Arborvitae trees, standing shoulder to shoulder, have become the de-facto fences of suburbia.

A typical builder installation of Arborvitae

Without room to spread their branches or reach their natural height, Arborvitae is often topped and heavily pruned to form hedges. They handle this assignment very well, but Arborvitae can do so much more!

If you’ve only seen Arborvitae used as a hedge, it may surprise you to learn that in its natural habitat, it can grow 50 to 60 feet tall and live for hundreds of years! In fact, the largest known specimen is over 100 feet tall and more than 40 feet wide at the crown. The oldest living Arborvitae is thought to have germinated from seed in 952 A.D., and is now 1,071 years old! Based on ring counts on dead trees, there are verified specimens of Arborvitae that lived to be over 1,800 years old.

An ancient stand of Arborvitae on cliffs overlooking
Northern Lake Michigan
*Photo: C.J. Earle*

Arborvitae is one of the common names for Thuja occidentalis and means “tree of life” in Latin. It was named by the French sea captain, Jacques Cartier, when he was exploring Canada in 1536. After months at sea, Cartier’s crew, including two young members of the Huron native tribe who had been sailing with them, were all suffering from scurvy. On the way up the St. Lawrence River, Cartier dropped the two young men at their home village. When he later returned, he was astonished to find the two Hurons fully recovered from all symptoms of scurvy while his French sailors were still suffering. He asked the Huron elders to teach him the cure, and they showed him how to make a medicine, a tea rich in Vitamin C, from the foliage of Thuja occidentalis. Cartier brought the life-saving plant back to France, making it the first North American tree introduced to Europe.

The native habitat of Thuja occidentalis is swamps, low woods, and forest edges from northern Canada south to New York and Connecticut and west to Michigan and Northern Indiana. It is an
evergreen conifer, extremely cold hardy, and adapted to poor rocky soils all the way to the edge of the Canadian tundra. Sometimes called Northern White Cedar, Eastern White Cedar, or
Swamp Cedar, Arborvitae is not a true cedar in the Cedrus family, none of which are native to North America. But the fragrance of its foliage and bark, and the usefulness of its wood, are similar.

Arborvitae often grows in very thin, poor soil in northern
North America and is adapted to extreme cold. This forest of
Arborvitae is at the brink of the Niagara Escarpment in Northern Wisconsin.
*Photo: C.J. Earle*

The foliage of Arborvitae is flat and scale-like and has a spicy fragrance when crushed. Native peoples used it not only for medicine but also used the fragrant foliage as insect-repellant
bedding. They stripped the tree’s shredding bark to make rope and twine, and they found many uses for the rot-resistant wood, including canoe frames and roofing shingles.

Thuja occidentalis has significant value to wildlife. It is a favorite food of white-tailed deer, as suburban homeowners often discover to their dismay. Twigs and foliage of Arborvitae constitute as much as 10 to 25% of the winter diet of deer, who will browse it as high as they can reach. In northern forests, the tree also provides highly nutritious food for snowshoe hares, porcupines, red squirrels, and beavers. Many native birds find nesting sites in Arborvitae and insects to feed their young. The seeds are the preferred source of food for Pine Siskins, birds indigenous to the Northeastern US.

It is sadly ironic that one of the most-planted trees in suburbia is disappearing in the wild. Thuja occidentalis is listed as Threatened in Connecticut, Illinois, Kentucky, and Maryland and Endangered in Indiana, Massachusetts, and New Jersey. Development is the primary culprit as forests are cleared to make way for more suburban homes.

It is equally sad that the rows and rows of Arborvitae planted on suburban property lines are not nearly as valuable to wildlife as they should be. The most popular varieties of Arborvitae are cultivars or hybrids that offer little value to wildlife – other than deer. A cultivar called ‘Emerald Green’ Arborvitae was developed in the 1950s in Denmark, just in time for the rapid expansion of the US suburbs after WWII. It quickly became the ubiquitous hedge plant we see all around us. In a tight hedge, and with limited biological diversity due to clonal reproduction by nurseries, its value to insects and birds is limited.

Another Arborvitae popular with builders is a hybrid called ‘Green Giant,’ which is a cross between a species indigenous to the Pacific Northwest and a Japanese species. As a hybrid between two non-natives, ‘Green Giant’ has very little value to insects or birds in this part of the country. If you can find the straight species of Thuja occidentalis (without a cultivar name), plant that. If not, ‘Emerald Green’ is a better choice than ‘Green Giant.’

Thuja occidentalis is an amazing tree. It deserves to be more than a fence! Given enough room to take its natural form, Arborvitae merits a starring role in suburban landscapes.

Growing the way nature intended, Arborvitae takes its
rightful place with Oaks, White Pines, and Junipers in
Northeastern landscapes

In our last blog post [Privacy Without “O-fence“], we urged homeowners to diversify their hedges and privacy screens by planting a mix of native trees and shrubs to increase habitat and biodiversity. Too much of any one plant becomes a mono-culture, limiting resources for wildlife. Unfortunately, that is what has happened to this magnificent native tree.

Don’t limit Arborvitae to this poor fate

Think of Arborvitae as an easy-care, long-lived, medium-sized, native, hardy evergreen that will enhance your landscape as part of a diverse planting of trees, shrubs, and perennials. You won’t
be sorry!

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

Share this post:

TO SUBSCRIBE TO THE BLOG – AND NOTHING ELSE – ENTER YOUR EMAIL BELOW

Suburban yards are places for families and friends to relax, perhaps enjoy a barbecue, and watch children and pets play safely. Privacy is important.

No wonder, then, that suburban homeowners often decide to plant a “privacy screen.” Hedges of trees or shrubs, planted as living “green fences,” are as common in suburbia as the lawns they typically surround.

But too often, these hedges are made with invasive plants that spread themselves into natural areas causing ecological harm. Top offenders include privet, Japanese barberry, forsythia, bamboo, and burning bush. All of these plants are recognized as invasive species and should be avoided.

Forsythia is not a good choice for a privacy screen

Burning Bush — Burning bush may look good for a minute

Japanese barberry, now banned in several states, spreads by seed into vacant lots, woods, and roadsides and actually increases the population of ticks carrying Lyme disease!

The good news is that the need for privacy does not require bringing any of these offensive plants onto your property. There are so many better choices!

In the Eastern US, the most popular privacy screen by far is Arborvitae (Thuja occidentalis), also known as Northern White-cedar. Favored by builders and landscape maintenance companies, a row of inexpensive and readily available Arborvitae is often planted along the property line as soon as a new house is built.

Though Arborvitae is a much better choice than any of the invasive plants mentioned above, it is not the only — or best — option. In areas populated by deer, Arborvitae is extremely vulnerable.

Here are some alternatives – beautiful evergreen trees and shrubs, native to the Northeast, that make ideal privacy screens. And because they are native, they also offer value to native birds and pollinators!

American Holly (Ilex opaca) makes a dense, evergreen privacy screen and has the bonus of tiny flowers for pollinators in the spring and beautiful berries that add winter interest to the landscape.

American Holly may be pruned into a hedge

Rhododendron is another good choice for privacy. When European settlers first explored the Eastern US, they struggled through massive stands of Rhododendron maximum that formed impenetrable evergreen thickets. Why not use that same feature now as an effective screen? Our native songbirds love to hide in a thicket!

Inkberry (Ilex glauca), another native evergreen, grows quickly and has shiny, dark green leaves that form a dense screen. More winter-hardy than boxwood and growing taller, Inkberry is a great hedge plant.

Red Twig Dogwood and Switch Grass — Inkberry in a mixed border with Red Twig Dogwood and Switch
Grass

The very best privacy screen, though, is not a row of one species of plant, but a forest! The Northeastern US was once predominantly forest, and many of the plants in those forests are still the best plants to grow here. In suburban yards, we can mimic the beauty, seclusion, and peaceful quiet of a diverse forest simply by planting more stuff! And a bigger variety of
that stuff is inspired by our native forests!

Maybe it’s time to reconsider our approach to the “privacy screen.”

Hedges can be great, but they can also be visually boring and ecologically sterile. There is no law requiring homeowners to mark their property boundaries with a row of identical plants. Just because your property line forms a rectangle doesn’t mean your landscape has to be one. A diverse mix of plants – native trees, shrubs, grasses, and perennials – planted in masses makes a landscape interesting, lush, ecologically valuable, and very private.

Contrasting approaches – the mixed border of deciduous and evergreen trees on the right offers more interest, and more privacy, than the hedge on the left

white pine, arborvitae, spruce, juniper, and Rhododendron — A mix of White Pine, Arborvitae, Spruce, Juniper, and
Rhododendron completely screens a house from the road

If you already have a hedge or a fence along the property line, consider planting inside it using a mix of native trees and shrubs that change with the seasons. Start with the corners.

Trained landscape designers tend to avoid square corners and straight lines in their designed plantings. You can do the same thing. Map out curved beds that soften the corners and bring more plants further into your yard. Plant taller shrubs at the back, and choose flowering shrubs and perennials to plant in the foreground where you can enjoy them.

Fences along two neighboring properties meet to form a hard corner that is softened, and completely screened, by a curved planting of mixed trees, shrubs, and perennials

So, consider creating a privacy screen that looks more like a forest than a fence. By planting more plants, and a bigger variety of plants in more of your yard, you will have more privacy, more seasonal interest, less lawn to tend, and more habitat for birds, butterflies, and fireflies.

How’s that for a win-win-win-win?!