Hemlock (Tsuga sp.)
Hemlocks are handsome and stately evergreen trees, valued for their deep green color and graceful habit. Their dark, pyramidal appearance accented with distinctive drooping branches is very attractive. Several kinds of Hemlocks are native to North America. Western Hemlock (Tsuga heterophylla) and Mountain Hemlock (Tsuga mertensiana) prefer the mountain slopes of the Pacific coast region. Canadian Hemlock (Tsuga canadensis) and Carolina Hemlock (T. caroliniana) are common in eastern forests where they are, unfortunately, under siege by the woolly adelgid aphid. Normally they are long-lived trees. Reportedly, several Canada Hemlocks that date from William Penn’s arrival to the Philadelphia area 300 years ago are still living.
Hemlock’s relatively dense foliage and bushy growth habit provides valuable cover for nesting and roosting birds. Its cones attract many seed-eating songbirds, such as chickadees, catbirds, robins, grackles, goldfinches and song sparrows. Deer and small rodents browse the foliage
| Summary of Hemlock | ||
|---|---|---|
| Species of Hemlock | Size | Basic Requirements |
| Canadian Hemlock (Tsuga canadensis) | At 20 years height is 25’ with a spread of 10’. Mature height is 40 to 70’ with a spread of spread of 25 to 35’,. Growth rate is medium at 10 to 12’ per year. | Zones 3 through 7 (8); Full sun but can live in full shade, cool, acid, moist soils; no hot dry conditions, no air pollution |
| Carolina Hemlock (Tsuga caroliniana) | Mature height is 45 to 60’ with a spread of 20 to 25’ | Zones 4 through 7; Full sun but can live in full shade, cool, acid, moist soils; no hot dry conditions, air pollution tolerant |
| Western Hemlock (Tsuga heterophylla) | Mature height is 30 to 60’ with a spread of 20 to 25’ | Zones 6 ; Full sun or shade, acid moist soil, needs moisture laden atmosphere and cool summer temperatures |
| Mountain Hemlock (Tsuga mertensiana) | Mature height is 30 to 60’ with a spread of 20 to 25’ | Zone 5 ; Full sun or shade; acid moist soil, needs cool, moist, mountain conditions |
