In the last issue, we discussed wildlife that you may meet on the trail which also included some critters known to be toxic. In this installment, we’ll touch on some of the poisonous plants you may encounter on your ride, and that you want to avoid. A plant is considered poisonous or toxic if it causes any negative symptoms, even a mild rash.
The Center for Disease Control recommends wearing long sleeves, pants, and socks, as well as gloves to avoid skin contact with poisonous plants. It is not recommended that you get close to the plants to take a picture, for instance. If you aren’t sure whether you’ve been exposed to any of these plants, wash your clothes immediately after your ride and scrub your body in the shower to be sure.
Trail crews and advocacy organizations like SDMBA do a good job of clearing overgrowth away from trails in their regions. Their work benefits us all in not having to carefully ride our way through woodlands. But even given the rigorous work of trail crews, these toxic plants are fast-growing weeds who’s seeds can stay dormant in the soil for many years.
The general rule of thumb for identifying toxic plants in the wild (and a catchy iteration of a rhyme you may have learned as a kid) is: “leaves of three, let it be.” If you’re not sure whether or not you’ll be encountering toxic plants, websites like iNaturalist can show you the exact location of reported observations by other hikers or riders on the trail. Remember, look but don’t touch and if you think you’re in need of medical attention, call your doctor right away.
Poison Oak (Toxicodendron diversilobum)
Poison Oak (Toxicodendron diversilobum) is a woody, perennial shrub, or vine, that you will find throughout the western United States, and is native to California. If you are in a wooded area below 5000 feet of elevation you’re most likely going to be near or around poison oak. Poison oak causes an allergic reaction in humans that can be anything from a mild rash, to blisters that will last days or months. The most harmful way to come in contact with poison oak is through inhalation, which can happen if it is burned in a fire and then inhaled through the lungs (this can be cause for concern in wildfire regions). If you are affected, the CDC recommends you immediately rinse the skin with rubbing alcohol or a degreasing soap (such as dishwashing soap) as well as any clothing
Poodle-dog bush (Eriodictyon parryi)
Stinging Nettles (Urtica dioica)
- For Further Reading: “Wicked Plants: The Weed that Killed Lincoln’s Mother and Other Botanical Atrocities” by Amy Stewart
- For location specific information – inaturalist.org
- For information on treatment – calpoison.org, (800) 222-1222
- Detailed descriptions of local trails – mtbproject.com
- Plant database UC Davis – arboretum.ucdavis.edu/plant-database