Thuja occidentalis

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Thuja occidentalis
Light:Full Sun Part Shade
Moisture:Mesic Hydric
Hardiness:2
Soil pH:5.6-8.4
Evergreen
Height:49'
Width:16'
Speed:Slow
Blooms:Mid Spring-Late Spring
Open Woods Forest
Native to:
Edible Rating:PFAF Edibility RatingPFAF Edibility Rating
Medicinal Rating:PFAF Medicinal RatingPFAF Medicinal Rating
Tea:Yes
Poisonous

Thuja occidentalis (common name: american arbor-vitae)

Propagation: Seed - best sown when ripe in the autumn in a cold frame[1]. Stored seed germinates best if given a short cold stratification[1]. 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[2]. 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[2].

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[2].

Cultivation: Prefers a permanently moist soil[3], it is intolerant of dry soils[4]. A useful plant for very poorly-drained soils[5][6]. The best stands in America are on well-drained soils[4]. Grows well in heavy clay soils. Succeeds in sandy soils[7] and on chalk[6].

A very hardy tree, tolerating very cold winters with temperatures down to -46°c[6][8]. In cold weather the leaves turn brown, becoming green again in the spring[9]. It is usually slow growing and short-lived in cultivation in Britain and rarely looks thrifty[10][5]. However, there are some good specimens in western Britain[11][12]. Some cultivars are more healthy, 'Lutea' is growing very well in several places and 'Spiralis' is also growing well[5]. Trees live 200 - 300 years in the wild[9].

Sometimes planted as a timber tree in C. Europe[13].

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[8].

The wood and the foliage are strongly aromatic[9]. The crushed leaves have a scent of apples[5].

Range: Eastern N. America - Nova Scotia to Georgia, west to Illinois and Minnesota.

Habitat: Swamps and cool rocky banks of streams[14], forming dense almost impenetrable forests[15][16]. Also found on rocky soils[9]. Plants are usually found on neutral to alkaline limestone soils[9].

Edibility: Pith of young shoots - cooked[17]. It can be added to soups[18]. Pleasantly sweet, the pith was used as the basis of the soup according to one report[19].

Inner bark - cooked. It is only used in times of emergency or scarcity[20]. 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[21][18][22] but are probably best avoided by pregnant women[16]. An aromatic flavour[19]. Another report says that the foliage and bark are used, the resulting tea is a good source of vitamin C[9].

Medicinal: 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[23][22]. 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[23]. The plant can be used to induce menstruation and so should not be prescribed for pregnant women[8].

The recently dried leafy young twigs are alterative, anthelmintic, anti-inflammatory, antiseptic, aromatic, astringent, diaphoretic, diuretic and emmenagogue[11][24][25][16]. The plant is being used internally in the treatment of cancer[8], especially cancer of the uterus[23]. A tea made from the leaves is used in the treatment for bronchitis and other respiratory problems, colds, headaches and as a cough syrup[26][23]. The plants diuretic properties make it useful in treating acute cystitis and bed-wetting in children[23]. The leaves are used in steam baths in the treatment of rheumatism, arthritis, colds etc[26]. Externally, the leaves are used as a wash for swollen feet and burns[26]. 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[23]. A tincture of the leaves has been used in the treatment of warts, piles, bed sores and fungal infections[26]. The leaves and young twigs can be harvested as required and used fresh or dried[8].

'Oil of white cedar', obtained from the leaves, is an essential oil that is antiseptic, expectorant and rubefacient[20][26]. It is used internally to promote menstruation and relieve rheumatism[20]. This volatile oil is toxic and poisoning from overdoses has occurred[20], it should only be used under the supervision of a qualified practitioner and should not be prescribed for pregnant women[8]. The oil also stimulates the heart and causes convulsions in high doses[20].

A tea of the inner bark is used to promote menstruation[20] and in the treatment of consumption and coughs[26].

A homeopathic remedy is made from the leaves and twigs, gathered when the tree is flowering[27]. 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[24][27].

Usage: Tolerant of regular trimming, though not into the old wood, it can be grown as a hedge[9].

The fresh branches are used as besoms[11]. Their aromatic smell serves to deodorize the house whilst sweeping[9].

The leaves have been kept in the clothes cupboard as a perfume, incense and insect repellent[22]. The leaves and stems have been used as an incense[22].

An essential oil is obtained from the leaves and branches, it is used in perfumery and in medicines[28][29][30][9]. It is poisonous if taken internally[31]. This essential oil also has insect repellent properties[32].

The tough and stringy bark has been used to weave fibre bags[22].

The bark is a source of tannin[22].

Wood - light, soft, not strong, brittle, coarse grained, very durable, easily worked, does not warp[30][15][33][9][34]. It weighs 20lb per cubic foot[34]. Used especially where contact with water cannot be avoided, for canoes, garden buildings, shingles, posts etc[4][30][15][33][9].

Pollinators: Wind

Soil: Can grow in light, medium, and heavy soils.

In Leaf: Evergreen

Seed Ripens: Early Fall-Mid Fall

Flower Type: Monoecious

Heavy Clay: Grows in heavy-clay soils.

Known Hazards: An essential oil from the leaves is poisonous if taken in large doses[24][31]. This plant should not be used by pregnant women[16].

Links

References

  1. ↑ 1.0 1.1 Dirr, Michael and Charles Heuser. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press, 1987.
  2. ↑ 2.0 2.1 2.2 Sheat, Wilfrid. Propagation of Trees, Shrubs and Conifers. St Martin, 1948.
  3. ↑ Chittendon, Fred. RHS Dictionary of Plants. Oxford University Press, 1951.
  4. ↑ 4.0 4.1 4.2 Bean, William. Trees and Shrubs Hardy in Great Britain. Murray, 1981.
  5. ↑ 5.0 5.1 5.2 5.3 Mitchell, Alan. Conifers in the British Isles. Stationery Office Books, 1975.
  6. ↑ 6.0 6.1 6.2 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
  7. ↑ Brickell, Christopher. The RHS Gardener's Encyclopedia of Plants and Flowers. Dorling Kindersley Publishers, 1990.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 Bown, Deni. Royal Horticultural Society Encyclopaedia of Herbs and Their Uses. Dorling Kindersley, 1995.
  9. ↑ 9.00 9.01 9.02 9.03 9.04 9.05 9.06 9.07 9.08 9.09 9.10 Lauriault, Jean. Identification Guide to the Trees of Canada. Fitzhenry and Whiteside, 1989.
  10. ↑ Rushforth, Keith. Conifers. Batsford, 1991.
  11. ↑ 11.0 11.1 11.2 Grieve, Margaret. A Modern Herbal. Penguin, 1984.
  12. ↑ Hylton, Josie and William Holtom. Complete Guide to Herbs. Rodale Press, 1979.
  13. ↑ Tutin, Tom et al.. Flora Europaea. Cambridge University Press, 1964.
  14. ↑ Lyndon, Merritt. Gray's Manual of Botany. American Book Co, 1950.
  15. ↑ 15.0 15.1 15.2 Sargent, Charles. Manual of the Trees of North America. Dover, 1965.
  16. ↑ 16.0 16.1 16.2 16.3 Mills, Simon. The Dictionary of Modern Herbalism.
  17. ↑ Tanaka, Tyōzaburō. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing, 1976.
  18. ↑ 18.0 18.1 Kunkel, Günther. Plants for Human Consumption. Koeltz Scientific Books, 1984.
  19. ↑ 19.0 19.1 Facciola, Stephen. Cornucopia - A Source Book of Edible Plants. Kampong Publications, 1990.
  20. ↑ 20.0 20.1 20.2 20.3 20.4 20.5 Weiner, Michael. Earth Medicine, Earth Food. Ballantine Books, 1980.
  21. ↑ McPherson, Alan and Sue McPherson. Wild Food Plants of Indiana. Indiana University Press, 1977.
  22. ↑ 22.0 22.1 22.2 22.3 22.4 22.5 Moerman, Daniel. Native American Ethnobotany. Timber Press, 1998.
  23. ↑ 23.0 23.1 23.2 23.3 23.4 23.5 Chevallier, Andrew. The Encyclopedia of Medicinal Plants. Dorling Kindersley, 1996.
  24. ↑ 24.0 24.1 24.2 Chiej, Roberto. Encyclopaedia of Medicinal Plants. MacDonald, 1984.
  25. ↑ Lust, John. The Herb Book. Bantam Books, 1983.
  26. ↑ 26.0 26.1 26.2 26.3 26.4 26.5 Foster, Steven and Billy Tatum. Medicinal Plants of Eastern and Central North America. Houghton Mifflin, 1990.
  27. ↑ 27.0 27.1 Castro, Miranda. The Complete Homeopathy Handbook. Macmillan, 1990.
  28. ↑ Uphof, Johannes. Dictionary of Economic Plants. Weinheim, 1959.
  29. ↑ Schery. Robert. Plants for Man. Prentice Hall, 1972.
  30. ↑ 30.0 30.1 30.2 Usher, George. A Dictionary of Plants Used by Man. Constable, 1974.
  31. ↑ 31.0 31.1 Frohne, Dietrich and Hans Pfänder. J. A Colour Atlas of Poisonous Plants. Timber Press, 1984.
  32. ↑ Coon, Nelson. The Dictionary of Useful Plants. Rodale Press, 1975.
  33. ↑ 33.0 33.1 Hill, Albert. Economic Botany. The Maple Press, 1952.
  34. ↑ 34.0 34.1 Britton, Nathaniel and Addison Brown. An Illustrated Flora of the Northern United States and Canada. Dover Publications, 1970.


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