This is the tree, shrub, and vine identification project fact sheet for Thuja occidentalis, Emerald Green Arborvitae. This fact sheet may not be copied in part or in whole and submitted as one’s own project, but may be cited as a source of facts during one’s own research. See tree, shrub, and vine identification project main page for links to other plants, and evergreen shrub slideshow for pictures.
Plant Botanical Name: Thuja occidentalis
Common Name: Arborvitae, Emerald Green Arborvitae, White Cedar.
Family Name: Cupressaceae
Plant is Native to What Country: Northeast North America
Plant Height at Maturity: Thuja reaches a mature hight of 35-50 feet tall and 10-20 feet wide. Cultivar “Emerald Green” only reaches 15′ high and 5′ wide.
Plant Habit and Form: Single or multiple stemmed evergreen trees, conical in shape, with dense foliage. Can be upright and narrow in habit.
Foliage: Scale-like foliage, to 2 mm, often overlaps on stems. Foliage and twig branching are horizontal, producing “flattened” twigs. Color green to dark green in summer, becoming discolored and even brownish in winter. Cultivars have been bred to either stay green in winter or have bright green or yellow year round foliage.
Bark: Bark gray, smooth on young stems but becoming furrowed on older wood. Bark is reddish brown in the furrows.
Flower: Monoecious brown flowers borne singly at the branch tips.
Fruit/Seed: Seed enclosed in small, thin-scaled brown cones 0.33-0.5 inches in size. Cones tend to cluster towards the top of the branches.
Growing Requirements: Grows best in deep, moist soil of neutral PH, in full sun. Tolerates wide variance in PH, and wet soils. Grows in part shade but can become thin. Plants are tolerant of transplanting and can be sheared to regulate size.
Problems and Drawbacks: Arborvitae are a preferred food source for deer and multiple-stemmed plants often split apart in heavy snowstorms. Spider mites, Leaf miners, and bagworms bother arborvitae. Foliar burn can be a problem in harsh locations.
Special Uses: Used for privacy hedges and windbreaks. Some cultivars are used in foundation plantings. Cultivars are valued for their green or yellow foliage.
ID Tips/Remarks: Aromatic smell when crushed.
Bibliography: http://www.hort.uconn.edu/plants/t/thuocc/thuocc1.html, http://www.fs.fed.us/database/feis/plants/tree/thuocc/all.html#MANAGEMENT%20CONSIDERATIONS, http://plants.usda.gov/java/charProfile?symbol=THOC2