There are around 27 species of Arnica in the U.S., however, the official United Plant Savers’ priority species are A. acaulis, A. angustifolia, A. chamissonis, A. cordifolia, A. fulgens, A. latifolia, and A. sororia.
- common leopardbane (A. acaulis)
- narrowleaf arnica (A. angustifolia)
- Chamisso arnica (A. chamissonis)
- heartleaf arnica (A. cordifolia)
- foothill arnica (A. fulgens)
- broadleaf arnica (A. latifolia)
- twin arnica (A. sororia)
Asteraceae (Aster family)
Arnica is very pollinator-friendly and attracts many species of bees, butterflies, moths, and other insects. Arnica plants produce many small seeds that are wind-dispersed at the end of summer and beginning of fall. They can also grow off of pieces of their rhizome.
Arnica plants can be found in nearly every state in the U.S., but the species listed as being of a higher priority live primarily in the west, in the states of Alaska, Arizona, California, Colorado, Idaho, Michigan, Montana, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Washington, and Wyoming. The only notable exception to this is the common leopardbane, A. acaulis, which lives on the east coast in the states of Delaware, Florida, Georgia, Maryland, New Jersey, North Carolina, Pennsylvania, South Carolina, and Virginia.
Arnica plants live in parts of every province and territory in Canada.
As a general rule, Arnicas prefer part-shade to full-sun, and the amount of water needed varies wildly between the species. They like sandy soil and do best in meadows and conifer forests.
Status of Endangered/Threatened (by state):
Common leopardbane (A. acaulis) is “Endangered” in Florida, Maryland, and Pennsylvania.
Heartleaf arnica (A. cordifolia) is “Endangered” in Michigan.
Currently no North American species of Arnica has been evaluated by the IUCN Red List.
Part of Plant Used/Active Medicinal Compounds:
Arnica was used historically in an attempt to treat back pain, sore eyes, swelling, cuts, and bruises. These are similar to how natural medicine practitioners use them today. It is taken by mouth for sore throats and pain and applied externally primarily to bruises, but also to sprains and sore limbs. Arnica is also found in some sweets and hair products.
It is important to note that while the dosage traditionally used in food preparation is considered healthy, overdosing on arnica can lead to serious side effects including shortness of breath, increased blood pressure, heart damage, organ failure, comas, and has even resulted in death. This is more likely to occur if you ingest it, rather than using it externally.
Arnica is one of the more well known of the herbal medicines and has seen a rapid uptick in use in recent years. While this has led to an increase in cultivation, it has also led to an increase in wild-harvest that can prove harmful to more sensitive species in the genus.
Wild Harvesting Impact On Other Species and Lookalikes:
Several species of animals depend on arnica as a valuable food source. Arnica cordifolia, individually, makes up 24% of the diet of deer and elk populations in its native regions during the summer.
Recommendations For Industrial and Home Use:
Please use arnica responsibly, and talk to your doctor before using arnica or any other medicinal plant. If you can, purchase either cultivated arnica or wild-harvested species that haven’t been listed as being at-risk.
- EFloras. (n.d.). Arnica in Flora of North America. Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA. Retrieved September 9, 2019, from http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=102636
- Lady Bird Johnson Wildflower Center. (2015, January 15). Plant Database: Arnica. Results compiled from multiple publications. Retrieved September 9, 2019, from https://www.wildflower.org
- Reed, William R. (1993). Arnica cordifolia. In: Fire Effects Information System, (Online). U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/plants/forb/arncor/all.html (2019, September 9).
- USDA. (n.d.). Plants Profile for Drosera (sundew). Results compiled from multiple publications. Retrieved July 11, 2019, from https://plants.usda.gov/core/profile?symbol=DROSE
- U.S. National Library of Medicine. (2019, April 23). Arnica: MedlinePlus Supplements. Retrieved from https://medlineplus.gov/druginfo/natural/721.html