Cascara Sagrada
Rhamnus purshiana

Family: Rhamnaceae

What it is like

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

Rhamnus purshiana is an evergreen Tree growing to 10 m (32ft) by 6 m (19ft). See above for USDA hardiness. It is hardy to UK zone 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: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 10

Where it is found

Rich bottom lands and sides of canyons, usually in coniferous forests.

Western N. America - British Columbia to California.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 2

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

Medicine

Rating: 3

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

Other

Rating: 2

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

How it is grown

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

Propagating it: 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. 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. Cuttings of mature wood of the current year's growth, autumn in a frame. Layering in early spring.

Best place to grow:

Habit: Tree

Hardiness:

Growth:

Soil: Light (sandy), medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

There is the suggestion that this species could be mildly poisonous. 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 .

Its other names

Local names

Synonyms

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