White cedar (Thuja occidentalis) is also referred to as arborvitae and northern white cedar. The tree belongs to the Cupressaceae family and grows well in USDA hardiness zones 2 to 7. White cedar is a native of North America and is used for creating hedges, in parking-lot buffer strips and for the median strip planting on highways. White cedar is a slow-growing evergreen that reaches a mature height of 25 to 40 feet with a spread of 10 to 12 feet. The shape of the leaves is scale-like, with blades less than 2 inches long. White cedar has an upright, pyramidal growth habit.
The wood of white cedar is the lightest of all commercial woods in the country. The tree grows extensively around the Great Lakes and in Maine in pure and mixed stands. The tree grows mostly in swamps but is also found growing on uplands. The heartwood of white cedar is well resistant to termites and decay. The wood is easy to work, holds paint and glue well, and shows little dimensional change (tendency to swell and shrink). But the wood is soft, with low mechanical qualities such as bending strength or capacity for holding nails. Common uses are for posts and rustic fences. White cedar is also used for poles, shingles, lumber and specialty products.
White cedar grows best in moist or wet rich, fertile soil. It is easy to transplant when trees are root-pruned, balled and burlapped or potted. The tree likes a high level of humidity, being a native of swamps and wet soils. Still, it has some level of resistance to drought. White cedar foliage is susceptible to browning in winter. This is more common in the cultivars that have colored foliage and in trees planted on exposed sites open to cold wind.
Pests and Diseases
White cedar is susceptible to leaf blight, which causes brown spots on the foliage during late spring. The leaves give an appearance of being scorched, and then drop. A number of pests can infest white cedar. These include arborvitae leaf miner, which mines the foliage tips and cause them to turn brown. A variety of scales also infest the leaves and stems and are best controlled with the use of horticultural oil in the overwintering, dormant tree state. Foliage is also likely to get yellow and speckled if infested with mites, and a bagworm infestation can result in damage to large areas of foliage.