Rhamnus purshiana Seeds | (syn. Frangula )
LATIN NAME: Rhamnus purshiana (syn. Frangula purshiana)
COMMON NAME: Cascara Sagrada
Plant Profile
Cascara Sagrada (Rhamnus purshiana, syn. Frangula purshiana) is a deciduous shrub or small tree of the buckthorn family (Rhamnaceae), native to the Pacific Northwest of North America. It grows 5-12 m tall, with oval, prominently veined leaves, small greenish flowers and red berries ripening black. The aged bark is one of the world’s best-known herbal laxatives, regulated as a drug in several countries, and wild harvesting once threatened native stands.
Science & Biotechnology
Cascara sagrada is one of the few North American native drugs to enter the world pharmacopoeias. Its bark, aged at least a year to oxidise the harsh anthrones, supplies cascarosides — anthraquinone glycosides that stimulate colonic motility after bacterial activation. It was a standard OTC laxative in the United States until 2002, when the FDA reclassified stimulant laxatives as not generally recognised as safe due to inadequate long-term safety data; it remains official in European monographs for short-term constipation. Chronic use causes electrolyte loss and cathartic dependence, and fresh bark causes violent cramping and vomiting.
Within the Rhamnus group, Rhamnus purshiana (syn. Frangula purshiana) is of continuing interest to researchers working on plant diversity, seed biology and the selection of improved garden forms. This regulatory change substantially reshaped how herb is used and marketed in the United States, even though it remains available and used in various forms internationally and within traditional herbal practice. For researchers, plants like this one offer practical material for propagation studies and selection work.
Uses & Benefits
In the garden, Cascara Sagrada earns its place in borders, containers and mixed plantings, and it also rewards growers who raise plants for cutting, drying or kitchen use. Within its native range, living tree also contributes to Pacific Northwest forest understorey structure, entirely apart from any use of its bark. A plant that has settled in will get along with only routine care.
Buckthorns gave medicine cascara sagrada, the standardized anthraquinone laxative bark; they are strong, short-term professional herbs, while the sea-buckthorn branch of the family gives superfood berries.
Growing from Seed
Sow fresh seed of Cascara Sagrada under ordinary good conditions. A period of cold, moist stratification helps seed germinate evenly, after which it should be sown into a loose, humus-rich, well-drained mix. Bright light to partial shade suits this Pacific Northwest native well, and it typically establishes readily in cool, moist conditions reflecting its native coastal forest habitat. Sow the seeds evenly over the surface and cover lightly in a loose, well-drained seed compost, keep the sowing evenly moist, and give the pot or tray partial shade. Once the seedlings have made true leaves, pot them on individually and plant out when they are sturdy and conditions are right.
Our Take
Cascara Sagrada has real presence in the garden without demanding much in return. It is generous with beginners and their occasional misjudgements.
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