In Alberta there are two common species of native juniper shrubs, Common Juniper (Juniperus communis) and Creeping Juniper (Juniperus horizontalis). Both have been documented in ethnographic studies as having been traditionally used by First Nations. Common Juniper grows circumpolar and has a long tradition of use throughout the Northern Hemisphere. It is one of the most frequently used species for medicine and is often mentioned in medicinal texts. The two species are easy to tell apart as Common Juniper has leaves that are needle-like and the Creeping Juniper has leaves that are more scale-like, pressed like roof shingles along the stem.
I have recently become aware of a third species of Eurasian juniper that is commonly planted in Calgary, Savin Juniper (Juniperus sabina). It is so popular there is even a cultivated variety called “Calgary carpet”. Unlike the native species of juniper, Savin Juniper is noted for being toxic and potentially deadly poisonous if taken in large enough quantities. The major concern is that both Savin Juniper and Creeping Juniper are commonly planted ornamentals in the Calgary area and they are very difficult to tell apart. This is because they both have scale-like needles that are pressed against the stem. Further there is so much variation in the cultivated varieties of both that any potentially distinguishing characteristics become muddled up. I have closely examined branches of both and suspect that Savin Juniper tends to have shorter, wider scales, more often pressed against the stem as compared with Creeping Juniper. However, I am not confident to clearly distinguish between the two. One of the best ways of tell the difference would be habitat, looking at planted junipers with suspicion and assuming wild species are Creeping Juniper. In and around the Calgary area, however, one cannot exclude the possibility that Savin Juniper has escaped cultivation and is now growing wild in parks.
My concern would be of course that someone would harvest juniper berries or leaves from their own yard and an accidental poisoning could occur. Many claims on the toxicity of plants are not well documented and are often based on very limited evidence, better to be safe than sorry, I suppose is the philosophy there. Sometimes concerns regarding toxicity or inedibility are completely cultural and are not based on any significant evidence at all. For this reason I often find it worthwhile to look for sound research and evidence regarding toxicity.
A summary of my research found that Savin Juniper has a long history of use for inducing abortions. The essential oil is clearly toxic and can produce severe gastro-intestinal inflammation, the inability to urinate, congestion of the pelvic organs, fever, mental confusion, coma and death. A safe dose for consumption of the leaves and berries is not clear. I have concluded that tasting a couple berries would not be toxic, however, great caution should be exercised when consuming significant quantities of unidentified juniper in the Calgary area.
It is worth noting that it is likely safety concerns for Savin Juniper that have been indiscriminately extrapolated to other species of juniper including Common Juniper. It is frequently noted in books and online that care should be taken when ingesting juniper due to potential kidney toxicity. However, one study fed incredibly high doses of the essential oil of Common Juniper to rats without causing any toxicity to the kidneys. In another study small doses of the essential oil were even shown to have kidney protective effects in rats. The essential oil of Common Juniper is also used to make gin and so is safely consumed on a regular basis.
It is quite easy to comfortably identify Common Juniper compared with Savin Juniper. I feel very comfortable using this species on a regular basis for treating colds and flus, urinary tract infections and digestive issues. I would recommend that berries and leaves be preferentially harvested from this species as there is a good track record of safe use and there is good scientific evidence of its safety.
Here is a list of the references I investigated for anyone interested in more in-depth study on this topic:
Ahmed, S., Hasan, M.H. & Mahmood, Z.A. 2016, “Antiurolithiatic plants in different countries and cultures”, Journal of Pharmacognosy and Phytochemistry, vol. 5, no. 1, pp. 102-115.
Butani, L., Afshinnik, A., Johnson, J., Javaheri, D., Peck, S., German, J. B., & Perez, R. V. 2003, “Amelioration of tacrolimus-induced nephrotoxicity in rats using juniper oil”, Transplantation, vol. 76, no. 2, pp. 306‑311.
Casares, R. 1964, Juniperus sabina. Food, Cosmetics and Toxicology, vol. 2, 680-681.
Felter, H.W., Lloyd, J.U. 1898, King’s American Dispensatory. Available at : http://www.henriettes-herb.com/eclectic/kings/index.html [Accessed 01 Dec. 2016]
Jazayeri, S.B.e.a. 2014, “A preliminary investigation of anticholinesterase activity of some Iranian medicinal plants commonly used in traditional medicine”, DARU Journal of Pharmaceutical Sciences, vol. 22, no. 17.
Kress, K. 2010, Juniper Berry Toxicity, Available at: http://www.henriettes-herb.com/blog/juniper-toxicity.html [Accessed 01 Dec. 2016]
Madari, H. & Jacobs, R.S. 2004, “An Analysis of Cytotoxic Botanical Formulations Used in the Traditional Medicine of Ancient Persia as Abortifacients”, Journal of Natural Products, vol. 67, pp. 1204-1210.
Pages, N., Fournier, G., Baduel, C., Tur, N. & Rusnac, M. 1996, “Sabinyl Acetate, the Main Component of Juniperus sabina L’Hérit. Essential Oil, is Responsible for Antiimplantation Effect”, Phytotherapy Research, vol. 10, no. 5, pp. 438-448.
Pages, N., Fournier, G., Chamorro, G., Salazar, M., Paris, M. & Boudene, C. 1989, “Teratological evaluation of Juniperus sabina essential oil in mice”, Planta Medica, vol. 55, no. 2, pp. 144-146.
Papavassiliou M.J. 1937, “Sur deux cas d’intoxication par la sabine la permèabilité placentaire a l’essence de sabine”, Société de Médecine Légale, vol. 15, pp. 778-81.
Redziz, S.S. 2007, “The Ecological Aspect of Ethnobotany and Ethnopharmacology of Population in Bosnia and Herzegovina”, Collegium Antropologicum, vol. 31, no. 3, pp. 869-890.
Revue Therapeutique. 1843, La Lancette Francaise Gazette des Hopitaux Civils et Militaires, book 5, vol. 2, pp. 588.
Schilcher H, Leuschner F. 1997. “The potential nephrotoxic effects of essential juniper oil”, Arzneimittelforschung, vol. 47, no. 7, pp. 855-8.
Shokrzade, M., Azadbakht, M., Ahangar, N., Naderi, H. & Saeedi Saravi, S.S. 2010, “Comparison of the cytotoxic effects of Juniperus sabina and Zataria multiflora extracts with Taxus baccata extract and Cisplatin on normal and cancer cell lines”, Pharmacognosy Magazine, vol. 6, no. 22, pp. 102-105.
Zhao, J., Liu, T., Xu, F., You, S., Xu, F., Li, C. & Gu, Z. 2016, “Anti-arthritic Effects of Total Flavonoids from Juniperus sabina on Complete Freund’s Adjuvant Induced Arthritis in Rats”, Pharmacognosy Magazine, vol. 12, no. 47, pp. 178-183.