Thuja occidentalis Arborvitae

Please note:  There are many nuances to using plants for food, beverage or medicinal treatment.  I may mention some of these with appropriate citations and/or references.  However, I have no professional experience and am not an authority in this area.  In no manner should any comments in these profiles be construed as recommendations or endorsement. 

Basic stats: 

Hardiness zones:  3-7 (7 is probably stretching it – they are a northern species after all)

Size:  Smallish to large – Really depends on the cultivar of which there are numerous. 

Growth rate:  slow to medium

Diseases/pests:  Bagworms, leaf miner, spider mites, heart rot and deer browsing. 

Cultural needs:  atmospheric moisture as well as soil moisture.  Prefers well-drained loam (well, who wouldn’t?).  Slightly acidic soil.

Longevity:  Long-lived in natural settings.  Specimen have been found over 1000 years old.    In landscape settings, we have seen 50 to 75-year-old trees still going strong. 

Side bar:  If you want to research old trees, check out this website:  Rocky Mountain Tree Ring Research.  http://www.rmtrr.org/oldlist.htm

Pruning care:  This also depends on the cultivar, your personal preference and/or landscape design.  It is always best to select a cultivar that is going to max out in size for the space you want filled.  (This is actually a cross-the-board recommendation for many plants as it will minimize pruning needs, which will be beneficial for its health and welfare as well your pocketbook.) 

Another reason people shear and/or shorten these trees is they simply think they should.  They see everyone else doing this and wrongly presume it is what the trees need. 

Availability:  I would rate availability as high.  If not already in stock, most nurseries should be able to order this species or the specific cultivar you need.   I have often seen them offered in balled in burlap and, generally speaking, they transplant well. 

The Arborvitae is an evergreen, meaning it retains green needles/leaves year-round.  (What that doesn’t mean is that those needles/leaves never drop.)   As a landscape plant, this species is very often planted in a tight row, creating a wonderful hedge which may act as a visual or physical barrier or as a delineation of space.  It may be incorporated in efforts at sound attenuation.

Please note when I included deer browsing under the Diseases/Pests section above, this was not an incidental comment.  These trees are actually utilized in deer yards as browse during bad winters.  Here in our area, you can gauge just how bad the winter was on wildlife by how hard the arborvitaes were hit. 

If you don’t want them eaten, protect them with fences.  I have also seen success with chunks of Irish Spring soap and products such as Liquid Fence.  No endorsement is intended on specific brands; these are just products I have happened to use myself or have had clients who also have used them.  There are other products which might be just as effective.

Another alternative after the plant has matured, is to prune the lower branches off.  You will still leave the main upright stems for a multi-stemmed plant. The tree is fully capable of growing well past the height of browsing and the cleared trunk can take on a majestic look as seen in a couple of the previous photos posted this blog.

Common names include Eastern white cedar, Northern white cedar, swamp cedar, American or eastern arborvitae.  These common names give you a hint as to its native habitat which is northeastern US and southeastern Canada and it grows in moist environments.  In my neck of the woods, it is most often simply called an arborvitae. 

You may have noticed the other common names for this tree use “cedar”.  However, it is not a true cedar.  By the way, there are no true cedars, (genus Cedrus, family Pinaceae) native to North America.  The Thuja occidentalis is a member of the Cuppressacea which includes the junipers of which the Juniperus virginiana is typically the species used in aromatic wood projects such as cedar chests.  However, the arborivate is very aromatic as well, as any tree worker who has chipped one will attest to:  on-the-job aromatherapy. 

The name “Arborvitae”, meaning “Tree of Life”, is by far the most colorful and descriptive as it literally could be viewed as such.  Jacques Cartier, an explorer for France in the mid-1500s, is credited with bestowing this name.  The tale relates how his second voyage to North America was locked in ice for five months.  He and his men endured bitter cold and the swollen limbs, rotting gums, loose teeth and excruciating pain of scurvy.  They survived by drinking a decoction provided by Huron guides made from the bark and leaves of a tree the Indians called annedda.  The French called it l’arbre de vie; in English “the tree of life”, in New Latin “arborvitae”.  (This information is gleaned from a book by Sheila Connor, New England Natives, pg 51.  A really fun read!)

One of my trips this last year, presenting at Plant Health Care workshops, took me to Como Park Zoo and Conservatory in St. Paul, Minnesota.  I stayed with a friend (who happens to be a plant pathologist); she attended the workshop as well.  While scoping out the venue, we met with the horticulturist who graciously introduced us to an approximately 500 year old Thuja occidentalis bonsai.  We were thrilled.  Trust me, a highlight of the trip.