Canadian Hemlock Facts

Tsuga canadensis, Canadian hemlock or Eastern hemlock, is an attractive ornamental shade tree that occurs naturally on mountainous slopes and ridges throughout the Eastern United States and Canada. Canadian hemlock is available in a variety of cultivars.

Identification

Canadian hemlock trees grow between 40 and 70 feet on average with a 15- to 30-foot spread. They have half-inch-long shiny green needles with silvery undersides and pyramid-shaped crowns with thorny drooping branches. They produce inconspicuous yellow or green leaves in April, followed by half-inch to one-inch oval-shaped brown cones.

Cultivation

Canadian hemlock trees prefer partial or full shade and well-drained, cool, moist acidic soil. They are hardy between USDA zones 3 and 7 and have little airborne salt tolerance and only moderate tolerance for drought. They require little pruning, according to the University of Florida IFAS Extension.

Considerations

According to the University of Florida IFAS Extension, many wild Canadian hemlock trees are severely infested with woody adelgid, an insect pest. Bagworms, mites, weevils, scale and many other pest species also feed upon Canadian hemlock trees. Canadian hemlocks are also susceptible to cankers and needle rust; however, they are resistant to Verticillium wilt, a devastating tree disease.

References

• Lady Bird Johnson Wildflower Center: Tsuga Canadensis
• North Carolina State University: Tsuga Canadensis
• University of Florida IFAS Extension: Tsuga Canadensis

Resources

• The United States National Arboretum: USDA Plant Hardiness Zone Map