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Rhamnus purshiana - DC.

Common Name Cascara Sagrada
Family Rhamnaceae
USDA hardiness Coming soon
Known Hazards There is the suggestion that this species could be mildly poisonous[19, 65]. Excessive use can cause cramps and diarrhoea. Limit treatment to 8-10 days. Long term use can be habit forming. Fresh cascara can cause a bloody diarrhoea and vomiting. It should be aged for at least 1 year or heat treated. Do not use on children [301].
Habitats Rich bottom lands and sides of canyons, usually in coniferous forests[60, 82].
Range Western N. America - British Columbia to California.
Edibility Rating    (2 of 5)
Other Uses    (0 of 5)
Weed Potential No
Medicinal Rating    (3 of 5)
Fully Hardy Moist Soil Semi-shade Full sun
Rhamnus purshiana Cascara Sagrada

Rhamnus purshiana Cascara Sagrada


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UPDATE 15/2/2012: Rhamnus purshiana DC. is a synonym of Frangula purshiana Cooper

Physical Characteristics

 icon of manicon of cone
Rhamnus purshiana is an evergreen Tree growing to 10 m (32ft) by 6 m (19ft).
It is hardy to zone (UK) 7. It is in leaf all year, in flower from May to June, and the seeds ripen in October. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects.
It is noted for attracting wildlife.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.


Frangula purshiana. (DC.)Cooper., Rhamnus purshiana


Edible Uses

Fruit - raw or cooked[2, 118, 161, 257]. A thin, rather juicy flesh[82]. It is sometimes eaten[183]. There is some debate as to whether the fruit is edible or slightly toxic[226]. The fruit is about 10mm in diameter[200] and contains 2 - 3 small seeds[229]. An extract of the bark, with the bitterness removed (by drying?) is a common flavouring for soft drinks, baked goods and ice cream[183].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Cascara sagrada is widely used as a gentle laxative that restores tone to the bowel muscles and thus makes repeated doses unnecessary[226, 244]. It is often sold in chemists etc[226]. The bark is used, this is harvested on a commercial basis from wild trees and plantations in western N. America[226]. 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[95, 213]. Three year old bark is considered to be the best age[4]. It is considered suitable for delicate and elderly persons and is very useful in cases of chronic constipation[4]. The bark also has tonic properties, promoting gastric digestion and appetite[1, 4, 11, 21, 57, 94, 95, 165]. As well as its uses as a laxative, it is taken internally in the treatment of digestive complaints, haemorrhoids, liver problems and jaundice[238]. This remedy should be used with caution since in excess it causes vomiting and diarrhoea[238]. It should not be prescribed for pregnant or lactating women, or patients with intestinal obstruction[238]. 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[238]. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Rhamnus purshiana for constipation (see [302] for critics of commission E).

Other Uses

A green dye is obtained from the bark[99, 118, 257]. Plants are sometimes grown in America as an ornamental hedge[229]. Wood - light, soft, not strong. Used for making the handles of small tools[82, 99].

Cultivation details

Succeeds in any reasonably good soil in sun or partial shade[11, 238]. This species is hardy to at least -15°c[238]. Closely related to R. frangula[11]. This species is cultivated as a medicinal plant in N. America[57, 60, 61] and is also collected from the wild[238]. It is becoming rare in the wild because of over-collection[238]. The flowers are produced in small clusters on shoots of the current year's growth[82]. A good bee plant[94]. The species in this genus are notably resistant to honey fungus[200].


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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[200]. 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[113]. Cuttings of mature wood of the current year's growth, autumn in a frame. Layering in early spring[4].

Other Names

If available other names are mentioned here

Found In

Countries where the plant has been found are listed here if the information is available

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status

IUCN Red List of Threatened Plants Status :

Related Plants
Latin NameCommon NameEdibility RatingMedicinal Rating
Rhamnus alaternusItalian Buckthorn00
Rhamnus carolinianusIndian Cherry, Oak, Carolina Buckthorn21
Rhamnus catharticaCommon Buckthorn03
Rhamnus croceusRed Berry20
Rhamnus dahuricaDahurian Buckthorn11
Rhamnus frangulaAlder Buckthorn03
Rhamnus globosalokao00
Rhamnus grandiflora 20
Rhamnus japonicaJapanese buckthorn11
Rhamnus leptophyllus 10
Rhamnus lycioides 00
Rhamnus nepalensis 11
Rhamnus persicus 20
Rhamnus purpureus 01
Rhamnus saxatilisAvignon Berry, Rock buckthorn00
Rhamnus saxatilis tinctoriusDyer's Buckthorn00
Rhamnus triquetra 01
Rhamnus utilisChinese Buckthorn00
Rhamnus virgatus 11


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