Practical
Plants

Thuja occidentalis

American Arbor-Vitae

a perennial woody evergreen member of the Thuja genus in the family Cupressaceae.

No photo available

Taxonomy and growth

Genus
Thuja
Life cycle
perennial
Foliage
evergreen
Woodiness
woody
Growth rate
slow
Height
15 m
Spread
5 m
Fertility
Wind
Flower type
monoecious
Pollinators
Wind

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

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

An essential oil from the leaves is poisonous if taken in large doses[31][30]. This plant should not be used by pregnant women[8].

Edible uses

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

Pith of young shoots - cooked[2]. It can be added to soups[10]. Pleasantly sweet, the pith was used as the basis of the soup according to one report[11]. Inner bark - cooked. It is only used in times of emergency or scarcity[16]. The inner bark can be dried and ground into a powder, then used with wheat or other cereals in making bread, biscuits etc. The leafy branchlets are used as a tea substitute[7][10][23] but are probably best avoided by pregnant women[8]. An aromatic flavour[11]. Another report says that the foliage and bark are used, the resulting tea is a good source of vitamin C[18].

Plant part
Stem
Product or use
Tea

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.

American arbor-vitae was much used by many native North American Indian tribes as a medicine to treat fevers, coughs, headaches, swollen hands and rheumatic problems[22][23]. The plant has an established antiviral activity and is most commonly used in modern herbalism to treat warts and polyps, being prescribed both internally and externally for these conditions[22]. The plant can be used to induce menstruation and so should not be prescribed for pregnant women[21]. The recently dried leafy young twigs are alterative, anthelmintic, anti-inflammatory, antiseptic, aromatic, astringent, diaphoretic, diuretic and emmenagogue[24][31][15][8]. The plant is being used internally in the treatment of cancer[21], especially cancer of the uterus[22]. A tea made from the leaves is used in the treatment for bronchitis and other respiratory problems, colds, headaches and as a cough syrup[17][22]. The plants diuretic properties make it useful in treating acute cystitis and bed-wetting in children[22]. The leaves are used in steam baths in the treatment of rheumatism, arthritis, colds etc[17]. Externally, the leaves are used as a wash for swollen feet and burns[17]. Extracts of the leaves can be painted on painful joints or muscles as a counter0irritant, improving local blood supply and thus facilitating the removal of toxins, easing pain and stiffness[22]. A tincture of the leaves has been used in the treatment of warts, piles, bed sores and fungal infections[17]. The leaves and young twigs can be harvested as required and used fresh or dried[21]. 'Oil of white cedar', obtained from the leaves, is an essential oil that is antiseptic, expectorant and rubefacient[16][17]. It is used internally to promote menstruation and relieve rheumatism[16]. This volatile oil is toxic and poisoning from overdoses has occurred[16], it should only be used under the supervision of a qualified practitioner and should not be prescribed for pregnant women[21]. The oil also stimulates the heart and causes convulsions in high doses[16]. A tea of the inner bark is used to promote menstruation[16] and in the treatment of consumption and coughs[17]. A homeopathic remedy is made from the leaves and twigs, gathered when the tree is flowering[19]. It is used in the household as a treatment against warts, but also has a range of other applications that should only be prescribed by a competent homeopath[31][19].

Product or use
Alterative
Product or use
Anthelmintic
Product or use
Antiinflammatory
Product or use
Antiseptic
Product or use
Aromatic
Product or use
Astringent
Product or use
Diaphoretic
Product or use
Diuretic
Product or use
Emmenagogue
Product or use
Homeopathy
Product or use
Rubefacient

Material uses

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

Tolerant of regular trimming, though not into the old wood, it can be grown as a hedge[18]. The fresh branches are used as besoms[24]. Their aromatic smell serves to deodorize the house whilst sweeping[18]. The leaves have been kept in the clothes cupboard as a perfume, incense and insect repellent[23]. The leaves and stems have been used as an incense[23]. An essential oil is obtained from the leaves and branches, it is used in perfumery and in medicines[26][28][29][18]. It is poisonous if taken internally[30]. This essential oil also has insect repellent properties[3]. The tough and stringy bark has been used to weave fibre bags[23]. The bark is a source of tannin[23]. Wood - light, soft, not strong, brittle, coarse grained, very durable, easily worked, does not warp[29][34][9][18][20]. It weighs 20lb per cubic foot[20]. Used especially where contact with water cannot be avoided, for canoes, garden buildings, shingles, posts etc[4][29][34][9][18].

Product or use
Broom
Product or use
Essential
Product or use
Fibre
Product or use
Incense
Product or use
Repellent
Product or use
Tannin
Product or use
Wood

Ecology and functions

Ecosystem niche
Canopy

Environment

Range
Eastern N. America - Nova Scotia to Georgia, west to Illinois and Minnesota.
Habitat
Swamps and cool rocky banks of streams[25], forming dense almost impenetrable forests[34][8]. Also found on rocky soils[18]. Plants are usually found on neutral to alkaline limestone soils[18].
Light
full sun
Shade tolerance
light shade
Water
high
Hardiness
Zone 2+
Soil textures
sandy, loamy, clay, heavy clay
Soil pH
acid, neutral, alkaline, very alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

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

Seed - best sown when ripe in the autumn in a cold frame[5]. Stored seed germinates best if given a short cold stratification[5]. It can be sown in a cold frame in late winter. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. If growing large quantities of plants, the seed can be sown in an outdoor seed bed in mid spring[32]. Grow the plants on for two years and then plant them out into their permanent positions in late autumn or early spring. Cuttings of half-ripe wood, 5 - 8cm with a heel, July/August in a shaded frame. Forms roots by the end of September but it should be overwintered in a frame[32]. Cuttings of almost ripe wood, 5 - 10cm with a heel, September in a cold frame. Forms roots in the following summer. Plant out in autumn or spring[32].

Cultivation

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

Prefers a permanently moist soil[1], it is intolerant of dry soils[4]. A useful plant for very poorly-drained soils[12][14]. The best stands in America are on well-drained soils[4]. Grows well in heavy clay soils. Succeeds in sandy soils[13] and on chalk[14]. A very hardy tree, tolerating very cold winters with temperatures down to -46°c[14][21]. In cold weather the leaves turn brown, becoming green again in the spring[18]. It is usually slow growing and short-lived in cultivation in Britain and rarely looks thrifty[33][12]. However, there are some good specimens in western Britain[24][6]. Some cultivars are more healthy, 'Lutea' is growing very well in several places and 'Spiralis' is also growing well[12]. Trees live 200 - 300 years in the wild[18]. Sometimes planted as a timber tree in C. Europe[27]. Plants cannot regenerate from old wood. Pruning is not normally necessary for this species, any pruning that is carried out should be done with care[21]. The wood and the foliage are strongly aromatic[18]. The crushed leaves have a scent of apples[12].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

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  2. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

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  3. Coon. N. The Dictionary of Useful Plants. Rodale Press 1975-00-00 ISBN 0-87857-090-x

    ↩

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

    ↩1↩2↩3

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

    ↩1↩2

  6. Holtom. J. and Hylton. W. Complete Guide to Herbs. Rodale Press 1979-00-00 ISBN 0-87857-262-7

    ↩

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

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  8. Mills. S. Y. The Dictionary of Modern Herbalism.

    ↩1↩2↩3↩4

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

    ↩1↩2

  10. Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169

    ↩1↩2

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

    ↩1↩2

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

    ↩1↩2↩3↩4

  13. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩

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

    ↩1↩2↩3

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

    ↩

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

    ↩1↩2↩3↩4↩5↩6

  17. 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↩5↩6

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

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9↩10↩11

  19. Castro. M. The Complete Homeopathy Handbook. Macmillan. London. 1990-00-00 ISBN 0-333-55581-3

    ↩1↩2

  20. 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

    ↩1↩2

  21. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

    ↩1↩2↩3↩4↩5↩6

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

    ↩1↩2↩3↩4↩5↩6

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

    ↩1↩2↩3↩4↩5↩6

  24. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2↩3

  25. Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950-00-00

    ↩

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

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

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  28. Schery. R. W. Plants for Man.

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

    ↩1↩2↩3

  30. Frohne. D. and Pf�nder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984-00-00 ISBN 0723408394

    ↩1↩2

  31. Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984-00-00 ISBN 0-356-10541-5

    ↩1↩2↩3

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

    ↩1↩2↩3

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

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  34. 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

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