Western Hemlock (Heterophylla)

The Western Hemlock (Heterophylla) is generally described as a perennial tree. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The greatest bloom is usually observed in the mid spring, with fruit and seed production starting in the summer and continuing until fall. Leaves are retained year to year. The Western Hemlock (Heterophylla) has a long life span relative to most other plant species and a slow growth rate. At maturity, the typical Western Hemlock (Heterophylla) will reach up to 170 feet high, with a maximum height at 20 years of 40 feet.

The Western Hemlock (Heterophylla) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, cuttings, seed. It has a moderate ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -23°F. has low tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Ethnobotanic: Western hemlock bark has high tannin content and was used as a tanning agent, pigment and cleansing solution (Pojar & MacKinnon 1994). Some Coast Salish people used a red dye made from hemlock bark to color mountain goat wool and basket materials and as a facial cosmetic and hair remover (Ibid.). The wood was heavy, durable, and fairly easy to carve. Implements such as children’s bows, spoons, combs, roasting pits, dip-net poles, and edges were carved from hemlock wood. The Mainland Comox threaded oolichan and herring boughs for drying, and used for drying, and used the boughs for lining steaming pits (Ibid.). Kwakwaka’wakw dancers wore headdresses, and head-bands of hemlock boughs, and young women lived in hemlock-bough huts for four days after their first menstruation (Ibid.).

Pitch obtained from crevices in the bark, has been chewed as a gum (Ibid.). Western hemlock leaves and shoot tips were used to make an herbal tea. The leaves and young shoots have been chewed as an emergency food to keep one alive when lost in the woods (Ibid.).

Medicinal: Western hemlock was commonly employed medicinally by several native North American Indian tribes who used it to treat a variety of complaints (Moerman 1998). Hemlock pitch was applied for a variety of purposes, including poultices or poultice coverings, linaments rubbed on the chest for colds and when mixed with deer tallow as a salve to prevent sunburn (Pojar & MacKinnon 1994). A decoction of the pounded bark has been used in the treatment of hemorrhages, diaphoretic, and diuretic (Moerman 1998). The powdered bark can be put in shoes for foot odor.

Landscaping & Wildlife: Tsuga heterophylla is occasionally planted as an ornamental tree in northern states and in Western Europe (Sargent 1961). Western hemlock stands provide cover and habitat for many wildlife species and small mammals. It is also used for nest trees by cavity nesting birds. This species is browsed by elk and deer. The seedlings are eaten by snowshoe hares and rabbits.

Agroforestry: Western hemlock is used in forested riparian buffers to help reduce stream bank erosion, protect aquatic environments, enhance wildlife, and increase biodiversity.

Economic: It is one of the best pulpwood for paper and paperboard products. The wood is used in house construction for external walls, structural support and is suited for interior finish, kitchen cabinets, flooring, and ceiling.

General Characteristics

General: Western hemlock (Tsuga heterophylla) is a large evergreen tree growing from ninety to two-hundred feet high. The needles are short stalked, flat, finely toothed, irregularly spare, and of unequal length (five to twenty millimeters long). The seed cones are ovoid, short-stalked, brown, with many thin papery scales, stalkless, and hanging down at the end of the twigs. The bark is smooth when young, reddish-brown, becoming darker, and deeply furrowed with flat-topped scaly ridges (Farrar 1995).

Required Growing Conditions

Western hemlock is native in northwestern California, Oregon, Washington, British Columbia, Alaska, Idaho, and Montana (McMinn & Maino 1963). In California, western hemlock occurs near the coast in scattered localities from Del Norte County southward to the vicinity of Elk Creek, Mendocino County (Ibid.). In Oregon and Washington, it inhibits the Coast Ranges and Olympic Mountains, extending eastward to the Cascades (Ibid.). For current distribution, please consult the PLANT Profile page for this species on the PLANTS Web site.

Adaptation Western hemlock occurs on a variety of soil types. This species is well adapted to grow on humus and decaying wood, and is also found on mineral soil (Pojar & MacKinnon 1994). This species is very shade tolerant and thrives in full sun and regenerates well under a closed canopy. Western hemlock grows in pure stands or mixed at lower levels with Douglas-fir, silver and grand firs, giant arborvitae, redwood, and hardwood and at higher elevations with noble fir, Alaska cedar, mountain hemlock, western, white, and lodgepole pines (Preston 1989).

Cultivation and Care

Propagation from Seed: Seed is best sown in a cold frame in the autumn or late winter. Dormancy is variable with some seed lots requiring cold stratification (Dirr & Heuser 1987). Stratification accelerates and improves total germination and, unless seeds are known not to require pretreatment, cold stratification at 41ºF from three weeks to three months is recommended (Ibid.). Young seedlings should be placed in individual pots, once they are large enough to handle, and allowed to grow in a cold frame. During early summer the following year, out plant seedlings to their permanent locations.

General Upkeep and Control

Seedling transplant well when they are 8 to 36 inches tall. However the best survival rate can be achieved if seedling are transplanted between 8 and 20 inches, this is usually when they are about five to eight years old (Huxley 1992). Transplanting larger seedlings will check badly and hardly put on any growth for several years. This slow growth predisposes the seedling to pest, poor root development and wind throws, and related damage. (Ibid.).

Plant Basics
Growth Rate Slow
General Type Tree
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Long
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Mid Spring
Displays Fall Colors No
Shape/Growth Form Single Stem
Drought Tolerance Low
Shade Tolerance Tolerant
Height When Mature 170
Vegetative Spread Slow
Flower Conspicuousness No
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Cuttings, Seed
Moisture Requirements Medium
Cold Stratification Required Yes
Minimum Temperature -23
Soil Depth for Roots 36
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 4.5–6 pH
Precipitation Range 38–38 inches/yr
Planting Density 300–1200 indiv./acre
Soil Textures Medium
Soil Depth for Roots 36
Minimum Frost-Free Days 150 day(s)
Salinity Tolerance None
CaCO3 Tolerance None
Sustainability & Use
Leaf Retention Yes
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA