Guest Post by Jocie Brooks

Here on the West Coast, we tend to boast about big trees, forever going on about massive firs and cedars. Sometimes, we are so mesmerized by these giants that we fail to notice many of the small but attractive trees that are also a fine feature of our forests. Showy dogwoods, delicate Douglas-maples, and elegant cascaras ply for our attention, and they deserve it!

One of my favourites of these seldom-noticed trees is the Cascara (Rhamnus purshiana). I’ve always thought that cascara is a pretty name for this airy, leafy-green tree. Spanish priests named it “Cascara sagrada” meaning “sacred bark” a reference to the tree’s medicinal value.

Cascara (Rhamnus purshiana) Leaves
The leaves of Cascara (Rhamnus purshiana) are prominently veined.

Cascara grows as a shrub or small tree (typically to about 10 metres tall) with thin silver-grey bark and glossy green leaves with prominent veins. In the spring, the unfurling leaves are a coppery colour, turning green when opened. Clusters of small greenish flowers are followed by purple-black berries that ripen in the summer. The berries are described in Plants of Coastal British Columbia by Pojar and MacKinnon as “edible but not incredible.” In the fall, the leaves turn attractive shades of yellow and salmon-pink before dropping off.

Cascara (Rhamnus purshiana) Berries
The berries of Cascara (Rhamnus purshiana) are described as “edible but not incredible.”

Cascara is found at lower elevations of Vancouver Island and along the south coast of the mainland north to Bella Coola. It also grows in the Southern Interior wet-belt around the Arrow and Kootenay Lake and Adams River region. It frequents dry to wet sites, often growing in shade mixed with conifers, or in wetter areas with red alder. Cascara is common and easy to find in our area, especially near rivers and streams.

Traditionally, cascara was used for several medicinal purposes, but it is mainly known for use as a laxative. Coastal peoples boiled dried bark to make a tea which was used as a purgative but also to cure headaches, heal sores and swelling, and internal strains. Care was taken to take only one strip from a tree, so that the tree would heal.

Extract from cascara bark started to be prescribed by doctors in the 1870’s. By the late 19th and early 20th century, cascara was being over harvested in Washington and Oregon and by 1915 cascara resources were in decline south of the border. Drug companies in the U.S began to look at cascara supplies in BC. Fortunately, recommendations for proper harvesting techniques in BC were first drawn up by the Provincial government in 1942. The Cascara Bark Regulation, created in 1958, ensured the long term conservation of the cascara tree.

According to the book Mr. Menzies’ Garden Legacy by Clive L. Justice, some very large cascaras, as big as 40 ft. high and 3 ft. wide, were stripped of their bark in the 1930’s from southern Vancouver Island and the southern Gulf Islands. Trees of this size are rare today- but out of curiosity I turned to the Big Tree Registry (available on-line) of BC to check out the stats on the largest cascara in the province. Surprisingly, the largest and only recorded giant cascara was recorded from Lannan Forest in Comox. The tree, documented by Chris Walther in 2003, was 1.09 metres in diameter and 17.77 metres high. Lannan forest was cleared for development in 2010.

After the outbreak of World War II the price of dried cascara bark rose dramatically, from 7 cents a lb to 20 cents a lb, which caused a frenzy of harvesting. There is quite a history of cascara bark collecting in our area, and many old-timers will still remember this practice. Through the depression and war years, cascara bark collecting was a popular means of supplementing one’s income. Richard Mackie, in his book Mountain Timber describes cascara bark collecting in the Comox Valley:

In July and August, many residents of clear-cut areas, especially those around Headquarters and Camp 3, peeled the medicinal bark of the small cascara tree (known to several logging families as “barberry”). They would dry the strips on their roofs or on their fences, pack them into burlap sacks, and take them to a second-hand dealer in Courtenay named William Douglas. He in turn sold it to mainland manufacturers…

By the 1960’s the development of synthetic laxatives greatly reduced the demand for cascara bark. In recent years there is a renewed interest in wild medicinal plants, and no doubt someone is still collecting cascara bark today.

Cascara is a nice tree to look at, but it’s history as a medicinal plant makes it even more interesting. A tree with laxative properties – who would have thought?