Q. We lost a few arbor-vitae shrubs last year and we want to replace them. Are they all the same?
A. There are different types of arbor-vitae based on the region where they come from. In general arbor-vitae prefer moist soils, partial shade, and protection from winter winds in our area. Once established, arbor-vitae can be a useful shrub for a privacy screen.
American Indians used arbor-vitaes in many ways. Ojibwa Indians are said to have made soup from the inner bark of the young twigs. The Potawatomi rolled up the bark into wads which served as torches. The timbers were also used to make the ribs in the Indians birch bark canoes .
The essential oil extracted from arbor-vitae is used in cleansers, disinfectants, hair preparations, insecticides, liniment, room sprays, and soft soaps. Powdered leaves are reported to kill flies in two hours, the vaporized leaf powder to kill ticks. Arbor-vitae wood contains a heat stable antibiotic useful as a food preservative. Used for poles shakes, shingles and siding.
Eastern White cedar (Thuja occidentalis) is an evergreen shrub native to the eEastern and Southern portions of the U.S. It is listed as endangered because it is now rare to find it growing in the wild.
Perhaps the most popular cultivar is Techny. Techny is a fast-growing columnar with a broad base. It is also one of the hardiest and toughest of the arborvitae. Rheingold has gold leaves that turn copper in winter. Emerald Green arbor-vitae is also popular. It has a finer texture, and is more narrow in form than Techny. Globe arbor-vitae is used as a foundation shrub. There are tons of other cultivars – some with gold foliage or distinct forms.
Western Red Cedar (Thuja plicata) is native to the Pacific Northwest. It is not as cold-hardy as Thuja occidentalis and is a bit coarser in texture.
Green Giant is a newcomer on the scene. It has dark foliage, and is reported to be more vigorous than other plicata cultivars. Western Red Cedar in general prefers cool, moist sunny to part sun conditions. Whipcord is an unusual newcomer to the trades. The dwarf form has stringy, pendulous branches that look like thin cords.
Oriental Red Cedar (Thuja orientalis) is the least hardy of all the Thujas. One could expect to see more cultivars appear on the scene with the recent plant-hardiness zone changes.
Bagworms find arbor-vitae very tasty, so it is important to scout each year for their presence. Deer also find the foliage of arbor-vitae tasty. Plicata cultivars are more likely to winter burn, though both species can brown up in the spring because desiccating winds can suck the moisture from the needles. Arbor-vitae limbs can also break under heavy snow loads or ice. Keep them pruned so this is less likely to occur.
All in all, arbor-vitae can be useful shrubs to use in our area. Read the tag to make sure you are using the species that best fits your local conditions.