Cascara, Frangula purshiana syn. Rhamnus purshiana, is also known as bearberry, cascara buckthorn, cascara sagrada, chittem, chitticum and Western buckthorn. It is not related to Uva ursi (also called bearberry). It is closely related to other buckthorns, including common buckthorn.
The name cascara comes from cáscara sagrada, Spanish for sacred bark, a name coined in the 17th century. It has been used for centuries by native Americans, and was “discovered” by Dr JH Bundy in 1877, subsequently marketed internationally, which resulted in the plant becoming endangered. Even today, 20% of laxatives sold in the US contain cascara extract.
Cascara is an evergreen tree native to North America which reaches a height of 10m (30′) and a spread of 6m (20′). It is not fussy as to soil type or pH but prefers moist soil. Like all trees, it will not grow in full shade.
Cascara sagrada can be used as a garden shrub which is attractive to wildlife, particularly bees. It is useful for areas where the soil is a bit too wet for other plants.
A green dye can apparently be made from the bark, but I don’t have any information as to the mordant to be used. The wood is soft, but sometimes used to make small tool handles and similar things.
Cultivation from seed requires stratification for 1-2 months, then sowing in early Spring in a cold frame. Pot on and grow on in a greenhouse until the following Summer, when plants can be ptaced in their final position. Alternatively take semi-ripe cuttings in July or August, or layer existing plants in Spring.
Although some people eat the fruit, some say it is (mildly) toxic. An extract from the bark is sometimes used as a flavouring for soft drinks (soda), baked goods and ice cream.
Cascara is not suitable for use by children, pregnant or nursing women, patients with intestinal obstruction or injuries, or anyone suffering from Crohn’s disease, irritable bowel syndrome, colitis, hemorrhoids, appendicitis, or kidney problems.
Do not use cascara for more than 10 days in a row.
The part used is the bark. This must be dried in the shade for at least 1 year and up to 3 years before use, or you can dry it out in a very cool oven for a few hours. Don’t use fresh bark, as it will cause diarrhea and vomiting. To make a decoction of bark: Put 30g dried aged bark in a small saucepan and add 2 cups of cold water. Bring to the boil, turn down to a simmer and continue cooking until the liquid is reduced by half. Strain off and discard the bark and take the liquid either as a single dose or split into three. Max. 1 cup a day.
The decoction is used as a gentle laxative especially suitable for elderly and delicate constitutions, also as an intestinal tonic. It is also sometimes painted on fingernails to discourage nail biting. It is approved for use in Germany for constipation.
As with all plants grown for medicinal use, it’s important to grow cascara organically. To find out more about growing organic herbs visit the Gardenzone.