Ohio Landscape Association

Plant Of The Month


It seems we have been trapped on the west coast this month as we discussed which plant to write about. As soon as we revisited the great redwood discussion of last month we ran into their neighbor, The Western Arborvitae.

This magnificent tree is native to a similar west coast range of Northern California (right at the coast, with coastal redwoods) up through the Pacific Northwest into the southern reaches of coastal Alaska. There is also a large swath in the Rocky Mountains that experiences much colder temperatures then their coastal cousins.

In its native habitat, this tree is another beast. It holds its own with Redwoods, Douglas Firs, and Western Hemlocks, reaching into the mid 200-foot range. Unlike a number of the plants associated with that ecosystem, the Western Arborvitae has shown much more tolerance to a broad range of conditions, allowing it to become very popular in the trade. Now found in gardens on most continents, this tree has become very popular in Western Europe and the Eastern/South Eastern United States.

Unfortunately for us here in the Midwest, climatic conditions do not allow the plant to reach its full height potential. While certain cultivars can still reach an impressive 30 to 40 feet (perhaps 50 in time) it seems laughable to the 200 plus of the west coast giants.

What the tree will make up for in its short coming is an incredibly fast growth rate and marked resistance to deer browse that we sorely lack in our native Eastern Arborvitae (Thuja occidentalis). There are a number of cultivars in the market, but the fastest grower is Green Giant,' which is actually a hybrid between T. plicata and T. standishii - a Japanese native. It is the mysterious "hybrid vigor" that allows Green Giant to push up to 24 inches of growth in the best of conditions. You may find a cultivar sold as Spring Grove,' which came from the cemetery of the same name in Cincinnati, though the consensus among professionals is that it is the same plant as Green Giant'.

You may see in Dr. Dirr's book that he doesn't speak as highly of this plant as one would expect. Keep in mind that a majority of his viewpoint is written from his home in Georgia, where the heat of summer is quite different than ours. No argument that he is a true plant genius, but sometimes his opinion can be dismissed as "southern people problems". This plant does exceptionally well for us in Ohio, and while it may exhibit some dulling of color in winter, we have not found it to be as extreme as Dr. Dirr leads on. Perhaps it is wise to keep this plant out of the harshest of winter winds to help maintain winter appeal.

While quite adaptable to planting sites, it would be ideal to provide - at minimum - part sun. True this plant will grow fine in the deep shade, though it may open up quite a bit and not provide the lush deep green screening most people desire. We also must make mention of a great screen planting of these we pass daily by our home that almost make a perfect screen. The issue is the first row of the 4 staggered rows has fried out from being too close to a 45 mph road. Salt spray drifting 15 feet off the road burned the plants foliage enough over two winters to completely kill them. Use caution in screen planting near salted areas, as this plant is not your best option (odd considering its native habitat near the Pacific Ocean!)

Perhaps the best uses of this plant is in a mass planting for visual and audio screening in either an informal screening or a true formal hedge. The plants stay narrow compared to their height, perhaps at most reaching 1/3 as wide as they are tall, so planting close together is quite alright to do - they will tolerate that just fine. Pruning into a formal hedge works with great effect, but keep in mind the overall height it wants to obtain. This is a fast grower, so expect a very tall hedge and a lot of very high ladder work to keep it looking good.

Scottish botanist David Don is credited with naming this species in the mid 1800's while he was the librarian for the Linnean Society of London (a pretty plant nerdy position to hold!) Plicata is a Latin based word (plicatus) which means folded as Mr. Don noticed the distinct folding pattern on the backside of the small leaves of the tree. Thuja (thew-ya) is a Greek derived word (thuia) for a similar tree from Northern Africa.

A number of common names exist with Western Arborvitae being the more often heard in the Midwest. Other names include Western Red Cedar, Giant Arborvitae, and Shinglewood (often used for shingles). The wood of this tree has long been used in construction, especially for wood that will be exposed to the elements due to high rot resistance. In fact, from most lumber yards this is the wood you are receiving when you purchase "cedar" as in cedar in your closet. There are a number of other trees that also fall under the name "cedar" in wood working, but that is a discussion for another day.

What may be most interesting about this plant is the common name of Arborvitae. Arbor which we know means "tree" and vitae meaning "life". Just as we may have to make curriculum vitae to represent all of the training and education we have gained in life (fancy way of saying resume) the Arborvitae is the Tree of Life.

This tree has a long history with Native American tribes in the Pacific Northwest of being a vital part to survival from canoes, to fish hooks from the roots, to extremely durable building materials, to clothing and baskets woven from the bark. There is also strong belief that there is a spirit that lives in these trees that looks over the people and gives them these gifts of life. Many even have a ceremony to perform to give thanks to the spirit before harvesting these gifts.

We think it is pretty neat to see people form such a strong bond with the trees that support their very life. In fact, all trees should be called arbor vitae as they are all responsible for our ability to have life!

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