Practical
Plants

Rhamnus purshianus

Cascara Sagrada

a perennial woody evergreen member of the Rhamnus genus in the family Rhamnaceae.

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Taxonomy and growth

Genus
Rhamnus
Life cycle
perennial
Foliage
evergreen
Woodiness
woody
Height
10 m
Spread
6 m
Fertility
Insects
Flower type
hermaphrodite
Pollinators
Insects

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.

There is the suggestion that this species could be mildly poisonous[8][22].

Edible uses

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

Fruit - raw or cooked[9][4][5][17]. A thin, rather juicy flesh[23]. It is sometimes eaten[7]. There is some debate as to whether the fruit is edible or slightly toxic[13]. The fruit is about 10mm in diameter[10] and contains 2 - 3 small seeds[14]. An extract of the bark, with the bitterness removed (by drying?) is a common flavouring for soft drinks, baked goods and ice cream[7].

Product or use
Condiment
Product or use
Drink
Plant part
Fruit

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.

Cascara sagrada is widely used as a gentle laxative that restores tone to the bowel muscles and thus makes repeated doses unnecessary[13][16]. It is often sold in chemists etc[13]. The bark is used, this is harvested on a commercial basis from wild trees and plantations in western N. America[13]. It should be harvested in the autumn or spring at least 12 months before it is used medicinally, in order to allow the more violent purgative effect to be mollified with age[25][12]. Three year old bark is considered to be the best age[18]. It is considered suitable for delicate and elderly persons and is very useful in cases of chronic constipation[18]. The bark also has tonic properties, promoting gastric digestion and appetite[1][18][2][11][19][24][25][6]. As well as its uses as a laxative, it is taken internally in the treatment of digestive complaints, haemorrhoids, liver problems and jaundice[15]. This remedy should be used with caution since in excess it causes vomiting and diarrhoea[15]. It should not be prescribed for pregnant or lactating women, or patients with intestinal obstruction[15]. An infusion of the bark is sometimes painted over finger nails in the hope that the bitter taste will deter the person from biting their nails[15].

Product or use
Laxative
Product or use
Purgative
Product or use
Tonic

Material uses

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

A green dye is obtained from the bark[26][4][17]. Plants are sometimes grown in America as an ornamental hedge[14]. Wood - light, soft, not strong. Used for making the handles of small tools[23][26].

Product or use
Dye
Product or use
Wood

Ecology and functions

Ecosystem niche
Canopy, Secondary canopy

Hedge

Environment

Range
Western N. America - British Columbia to California.
Habitat
Rich bottom lands and sides of canyons, usually in coniferous forests[20][23].
Light
full sun
Shade tolerance
light shade
Water
moderate
Hardiness
Zone 7+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

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

Seed - best sown in the autumn in a cold frame. Stored seed will require 1 - 2 months cold stratification at about 5° and should be sown as early in the year as possible in a cold frame or outdoor seedbed[10]. Prick out the seedlings into individual pots when they are large enough to handle, and grow them on in the greenhouse or cold frame for their first winter. Plant them out in late spring or early summer of the following year. Cuttings of half-ripe wood, July/August in a frame[3]. Cuttings of mature wood of the current year's growth, autumn in a frame. Layering in early spring[18].

Cultivation

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

Succeeds in any reasonably good soil in sun or partial shade[2][15]. This species is hardy to at least -15°c[15]. Closely related to R. frangula[2]. This species is cultivated as a medicinal plant in N. America[19][20][21] and is also collected from the wild[15]. It is becoming rare in the wild because of over-collection[15]. The flowers are produced in small clusters on shoots of the current year's growth[23]. A good bee plant[24]. The species in this genus are notably resistant to honey fungus[10].

References

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

    ↩

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

    ↩1↩2↩3

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

    ↩

  4. Gunther. E. Ethnobotany of Western Washington. University of Washington Press 1981-00-00 ISBN 0-295-95258-X

    ↩1↩2

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

    ↩

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

    ↩

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

    ↩1↩2

  8. Stary. F. Poisonous Plants. Hamlyn 1983-00-00 ISBN 0-600-35666-3

    ↩

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

    ↩

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

    ↩1↩2↩3

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

    ↩

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

    ↩

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

    ↩1↩2↩3↩4

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

    ↩1↩2

  15. 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↩7↩8

  16. Phillips. R. & Foy. N. Herbs Pan Books Ltd. London. 1990-00-00 ISBN 0-330-30725-8

    ↩

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

    ↩1↩2

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

    ↩1↩2↩3↩4

  19. Schery. R. W. Plants for Man.

    ↩1↩2

  20. Hitchcock. C. L. Vascular Plants of the Pacific Northwest. University of Washington Press 1955-00-00

    ↩1↩2

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

    ↩

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

    ↩

  23. 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

  24. Sweet. M. Common Edible and Useful Plants of the West. Naturegraph Co. 1962-00-00 ISBN 0-911010-54-8

    ↩1↩2

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

    ↩1↩2

  26. Turner. N. J. Plants in British Columbian Indian Technology. British Columbia Provincial Museum 1979-00-00 ISBN 0-7718-8117-7

    ↩1↩2

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