Herb: Canadian Hemlock

Latin name: Tsuga canadensis

Synonyms: Abies americana, Pinus canadensis

Family: Pinaceae (Pine Family)

Medicinal use of Canadian Hemlock:

Canadian hemlock was commonly employed medicinally by several native North American Indian tribes who used it to treat a variety of complaints. It is still sometimes used in modern herbalism where it is valued for its astringent and antiseptic properties. The bark is rich in tannin and is astringent and antiseptic. A decoction is used in the treatment of diarrhoea, colitis, diverticulitis and cystitis. Externally, it is used as a poultice to cleanse and tighten bleeding wounds, as a douche to treat excessive vaginal discharge, thrush and a prolapsed uterus, and as a mouthwash and gargle for gingivitis and sore throats. The poultice has also been applied to the armpits to treat itchiness there. The inner bark is diaphoretic and styptic. An infusion is used in the treatment of colds and abdominal pains. A decoction of the inner bark has been applied externally in the treatment of eczema and other skin conditions. The pulverized inner bark has been applied to cuts and wounds to stop the bleeding. A tea made from the leafy twig tips is used in the treatment of dysentery, kidney ailments, colds and rheumatism. Externally, it is used in steam baths for treating colds, rheumatism and to induce sweating. A decoction of the branches has been boiled down to a syrup or thick paste and used as a poultice on arthritic joints. A poultice of the crushed branch tips has been used to treat infections on an infants navel. Hemlock pitch has been used externally as a counter-irritant in the treatment of rheumatism.

Description of the plant:


20 m
(66 feet)



Habitat of the herb:

Woods and swampy areas on cool moist sites, also in upland forests, often covering the north side of ridges.

Edible parts of Canadian Hemlock:

Inner bark - raw or cooked. Usually harvested in the spring, it can be dried, ground into a powder and then used as a thickening in soups etc or mixed with cereals when making bread. An emergency food, it is only used when all else fails. The leaves and twigs yield "spruce oil", used commercially to flavour chewing gum, soft drinks, ice cream etc. A herbal tea is made from the young shoot tips. These tips are also an ingredient of "spruce beer".

Other uses of the herb:

Yields a resin similar to Abies balsamea, it is gathered by incisions in the trunk or by boiling the wood. A pitch (called hemlock pitch), is obtained by distillation of the young branches. "Oil of Hemlock" is distilled from the young branches according to another report. The bark contains 8 - 14% tannin. The inner bark is used according to one report. The inner bark has been used in making baskets. A red to brown dye is obtained from the bark. A red dye is obtained from the inner bark according to another report. A little rock dust has been added to act as a mordant when boiling the bark. The boiled bark has been used to make a wash to clean rust off iron and steel, and to prevent further rusting. Tolerant of light trimming, plants can be grown as a hedge. This species does not make a good hedge in Britain. Some cultivars can be grown as a ground cover when planted about 1 metre apart each way. "Pendula" is slow-growing but makes a very good cover. Wood - coarse-grained, light, soft, not strong, brittle, not durable outdoors. Difficult to work because it splits easily. The wood weighs 26lb per cubic foot. The trees do not self-prune and so the wood contains numerous remarkably hard knots that can quickly dull the blade of an axe. A coarse lumber, it is used occasionally for the outside of buildings. It should be used with caution as a fuel for outdoor fires because it can project embers and burning wood several metres from the fire.

Propagation of Canadian Hemlock:

Seed - it germinates better if given a short cold stratification and so is best sown in a cold frame in autumn to late winter. It can also be sown in early spring, though it might not germinate until after the next winter. If there is sufficient seed, an outdoor sowing can be made in spring. Pot-grown seedlings are best potted up into individual pots once they are large enough to handle - grow them on in a cold frame and plant them out in early summer of the following year. Trees transplant well when they are up to 80cm tall, but they are best put in their final positions when they are about 30 - 45 cm or less tall, this is usually when they are about 5 - 8 years old. Larger trees will check badly and hardly put on any growth for several years. This also badly affects root development and wind resistance.

Cultivation of the herb:

Woods and swampy areas on cool moist sites, also in upland forests, often covering the north side of ridges.

Known hazards of Tsuga canadensis:

None known

Plant information taken from the Plants For A Future.