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Plants

Tsuga canadensis

Canadian Hemlock

a perennial woody evergreen member of the Tsuga genus in the family Pinaceae.

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Taxonomy and growth

Family
Pinaceae
Genus
Tsuga
Life cycle
perennial
Foliage
evergreen
Woodiness
woody
Growth rate
moderate
Height
20 m
Spread
8 m
Fertility
Wind
Flower type
monoecious
Pollinators
Wind

Uses

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Inner bark - raw or cooked[12]. Usually harvested in the spring[8], it can be dried, ground into a powder and then used as a thickening in soups etc or mixed with cereals when making bread[8][21][4]. An emergency food, it is only used when all else fails[6]. The leaves and twigs yield 'spruce oil', used commercially to flavour chewing gum, soft drinks, ice cream etc[6]. A herbal tea is made from the young shoot tips[8][24][30][3][6][20]. These tips are also an ingredient of 'spruce beer'[6].

Product or use
Condiment
Product or use
Tea
Plant part
Inner bark

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

Canadian hemlock was commonly employed medicinally by several native North American Indian tribes who used it to treat a variety of complaints[20]. 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[13][19]. A decoction is used in the treatment of diarrhoea, colitis, diverticulitis and cystitis[19]. 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[13][19]. The poultice has also been applied to the armpits to treat itchiness there[20]. The inner bark is diaphoretic and styptic[11][12][20]. An infusion is used in the treatment of colds and abdominal pains[11][12][20]. A decoction of the inner bark has been applied externally in the treatment of eczema and other skin conditions[20]. The pulverized inner bark has been applied to cuts and wounds to stop the bleeding[20]. A tea made from the leafy twig tips is used in the treatment of dysentery, kidney ailments, colds and rheumatism[11][13][20]. Externally, it is used in steam baths for treating colds, rheumatism and to induce sweating[13]. A decoction of the branches has been boiled down to a syrup or thick paste and used as a poultice on arthritic joints[20]. A poultice of the crushed branch tips has been used to treat infections on an infants navel[20]. Hemlock pitch has been used externally as a counter-irritant in the treatment of rheumatism[12].

Product or use
Antipruritic
Product or use
Astringent
Product or use
Diaphoretic
Product or use
Diuretic
Product or use
Skin
Product or use
Styptic

Material uses

This section contains historical Plants For A Future notes marked noncommercial.

Yields a resin similar to Abies balsamea, it is gathered by incisions in the trunk or by boiling the wood[21][23][25]. A pitch (called hemlock pitch), is obtained by distillation of the young branches[21]. 'Oil of Hemlock' is distilled from the young branches according to another report[29]. The bark contains 8 - 14% tannin[21][5][14]. The inner bark is used according to one report[29]. The inner bark has been used in making baskets[20]. A red to brown dye is obtained from the bark[11][21][20]. A red dye is obtained from the inner bark according to another report[15]. A little rock dust has been added to act as a mordant when boiling the bark[20]. The boiled bark has been used to make a wash to clean rust off iron and steel, and to prevent further rusting[20]. Tolerant of light trimming, plants can be grown as a hedge[28]. This species does not make a good hedge in Britain[9]. Some cultivars can be grown as a ground cover when planted about 1 metre apart each way[10]. 'Pendula' is slow-growing but makes a very good cover[10]. Wood - coarse-grained, light, soft, not strong, brittle, not durable outdoors[11][21][23][29][5][16]. Difficult to work because it splits easily[15]. The wood weighs 26lb per cubic foot[17]. The trees do not self-prune and so the wood contains numerous remarkably hard knots that can quickly dull the blade of an axe[15]. A coarse lumber, it is used occasionally for the outside of buildings[11][21][23][29][5][16]. 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[15].

Product or use
Basketry
Product or use
Dye
Product or use
Resin
Product or use
Rust treatments
Product or use
Tannin
Product or use
Wood

Ecology and functions

Ecosystem niche
Canopy, Soil surface

Ground cover

Hedge

Environment

Range
Eastern N. America - Nova Scotia to Georgia, west to Alberta and Minnesota.
Habitat
Woods and swampy areas on cool moist sites[11], also in upland forests, often covering the north side of ridges[29].
Light
full sun
Shade tolerance
permanent shade
Water
moderate
Hardiness
Zone 4+
Soil textures
sandy, loamy, clay
Soil pH
very acid, acid, neutral, alkaline
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Seed - it germinates better if given a short cold stratification[27][2] 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[26]. 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[9]. Larger trees will check badly and hardly put on any growth for several years. This also badly affects root development and wind resistance[9].

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

An easily grown plant, it thrives best when growing in a deep well-drained soil in the western parts of Britain where it appreciates the higher rainfall[1]. However, it succeeds in most soils and positions, being especially good on acidic sandy soils[28] but also tolerating some lime[1] so long as there is plenty of humus in the soil[10]. Plants are very shade tolerant when young, but need more sunlight as they grow older[28][9]. Plants are thin and poor when grown in dry or exposed places[9]. A slow-growing but long-lived species in the wild, with specimens nearly 1000 years old recorded[16]. It is occasionally planted as a timber tree in Germany[22]. It is very slow growing in cultivation for the first few years, it then grows more rapidly with annual shoots up to 60cm long. This rate of growth soon slows as the tree loses apical dominance and it becomes slow growing again[7]. Seed production commences around the age of 20 - 40 years, with good crops produced every 3 - 4 years[16]. The crushed foliage has a sweet lemony scent[7]. Another report says that it emits the unpleasant smell of hemlock[18]. Many named forms have been selected for their ornamental value[7]. Almost all of them are dwarf forms[9]. Plants in this genus are notably resistant to honey fungus[9].

References

  1. Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00

    ↩1↩2

  2. Dirr. M. A. and Heuser. M. W. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press 1987-00-00 ISBN 0942375009

    ↩

  3. McPherson. A. and S. Wild Food Plants of Indiana. Indiana University Press 1977-00-00 ISBN 0-253-28925-4

    ↩

  4. Yanovsky. E. Food Plants of the N. American Indians. Publication no. 237. U.S. Depf of Agriculture.

    ↩

  5. Hill. A. F. Economic Botany. The Maple Press 1952-00-00

    ↩1↩2↩3

  6. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

    ↩1↩2↩3↩4

  7. Mitchell. A. F. Conifers in the British Isles. HMSO 1975-00-00 ISBN 0-11-710012-9

    ↩1↩2↩3

  8. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

    ↩1↩2↩3

  9. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5↩6↩7

  10. Thomas. G. S. Plants for Ground Cover J. M. Dent & Sons 1990-00-00 ISBN 0-460-12609-1

    ↩1↩2↩3

  11. Lust. J. The Herb Book. Bantam books 1983-00-00 ISBN 0-553-23827-2

    ↩1↩2↩3↩4↩5↩6↩7

  12. Weiner. M. A. Earth Medicine, Earth Food. Ballantine Books 1980-00-00 ISBN 0-449-90589-6

    ↩1↩2↩3↩4

  13. Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990-00-00 ISBN 0395467225

    ↩1↩2↩3↩4

  14. Rottsieper. E.H.W. Vegetable Tannins The Forestal Land, Timber and Railways Co. Ltd. 1946-00-00

    ↩

  15. Lauriault. J. Identification Guide to the Trees of Canada Fitzhenry and Whiteside, Ontario. 1989-00-00 ISBN 0889025649

    ↩1↩2↩3↩4

  16. Elias. T. The Complete Trees of N. America. Field Guide and Natural History. Van Nostrand Reinhold Co. 1980-00-00 ISBN 0442238622

    ↩1↩2↩3↩4

  17. Britton. N. L. Brown. A. An Illustrated Flora of the Northern United States and Canada Dover Publications. New York. 1970-00-00 ISBN 0-486-22642-5

    ↩

  18. Genders. R. Scented Flora of the World. Robert Hale. London. 1994-00-00 ISBN 0-7090-5440-8

    ↩

  19. Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996-00-00 ISBN 9-780751-303148

    ↩1↩2↩3

  20. Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998-00-00 ISBN 0-88192-453-9

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9↩10↩11↩12↩13↩14

  21. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩1↩2↩3↩4↩5↩6↩7

  22. ? Flora Europaea Cambridge University Press 1964-00-00

    ↩

  23. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩1↩2↩3

  24. Elias. T. and Dykeman. P. A Field Guide to N. American Edible Wild Plants. Van Nostrand Reinhold 1982-00-00 ISBN 0442222009

    ↩

  25. Howes. F. N. Vegetable Gums and Resins. Faber

    ↩

  26. Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00

    ↩

  27. McMillan-Browse. P. Hardy Woody Plants from Seed. Grower Books 1985-00-00 ISBN 0-901361-21-6

    ↩

  28. Rushforth. K. Conifers. Christopher Helm 1987-00-00 ISBN 0-7470-2801-X

    ↩1↩2↩3

  29. Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965-00-00 ISBN 0-486-20278-X

    ↩1↩2↩3↩4↩5

  30. Saunders. C. F. Edible and Useful Wild Plants of the United States and Canada. Dover Publications 1976-00-00 ISBN 0-486-23310-3

    ↩

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