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4 Harmful Plants to Avoid on the Trails

Exploring Nevada and all of the beautiful landscapes it has to offer seems to be something that most Reno residents enjoy. Whether it’s perusing the sandy shores of Lake Tahoe, meandering through the cool wetlands, or simply trekking along the Pinyon-Pine hills of the Toiyabe National Forest, all adventurers can agree that Nevada is home to a multitude of interesting flora. Although many plants that reside here are unique and interesting sights to see, some hold the ability to be harmful to humans and dogs alike. Below is a guide of the top 4 harmful plants you and your furry friends should avoid while on the trails, including how to identify them, where to find them, and the symptoms that occur if encountered or ingested.

Stinging Nettle - Urtica dioica

Identifying features: This plant lives up to its name due to the leaves having relatively intimidating serrations. Its scientific name, Urtica dioica, comes from the Latin word uro, which means “to burn,” because its leaves can cause a temporary burning sensation upon contact. Stinging nettle ranges from 2-5 feet in height with opposite, toothed leaves that are pointed at the end, and its stems are always singular. Both their leaves and stems have fine hairs that mimic hollow nettles with formic acid inside, which is the same chemical found in ant saliva!

Where it is commonly found: Stinging nettle loves to dwell in areas with lots of sunlight and in soils with high nitrogen, so they are most commonly found along stream banks, rivers, and lakes. They also thrive in areas of human destruction like in ditches, along railroads, in empty lots, and abandoned farm areas.

Symptoms and treatment: If skin comes in contact with this plant, the area will become: itchy, red, and create a non-spreading rash that can last for up to 24 hours. To treat, wash the area with soap and cool water. You may apply an antihistamine or hydrocortisone cream to relieve the itching and swelling. Symptom of contact are similar in dogs, so be sure to wash the area well and monitor for other symptoms. Signs of ingesting would be: panting, vomiting, excessive drooling, and pawing at the mount. If ingested, speak with your vet about treatment options immediately.

Pacific Poison Oak - Toxicodendron diversilobum

Identifying features: Identification is relatively​​ easy for this plant, thanks to the tale old rhyme “leaves of three, leave it be.” The three leaves are attached to an individual stem where two are positioned directly opposite of each other while the third juts out, forming a triangle. The coloring can be tinged red or green, can be glossy or dull, and can be oak shaped, or round. But as long as you remember “leaves of three, leave it be,” your skin will thank you.

Where it is commonly found: Poison oak has urus oil on the surface of its leaves and twigs, which causes an allergic reaction when exposed to skin, so remember to wear long pants when out and about! Be especially vigilant near roadsides, field margins, ditches, marshes, meadows, and other low-lying areas.

Symptoms and treatment: If an adventurer brushes up against this plant, they will have the following symptoms: itching, redness, swelling, and blistering on the skin. Removing and washing any clothing that came into contact with the plant, taking cool showers, and applying calamine lotion will help reduce exposure and relieve itchiness. The rash, however, could last anywhere from 1-2 weeks. Luckily, the risk for dogs is minimal as their fur offers protection against direct contact. Though, if ingested, it may cause stomach issues such as vomiting, diarrhea, or fever. The reactions may be mild, however it is always best to contact your vet for treatment options.

Poison Hemlock - Conium maculatum

Identifying features: To identify this plant, refer to the pictures. Notice that the white flowers are arranged in an umbel and the leaves are dark green, triangular in shape, and appear to be fern-like. The hairless stems are almost a dead giveaway with reddish-purple splotching along them, so be sure to keep an eye out for that.

Where it is commonly found; Poison hemlock likes lots of sunlight and is commonly found along bike paths, rivers, ditches, railways, and field edges.

Symptoms and treatment: All parts of this plant are lethal to humans (and animals) alike when ingested. Even after the plant has died, the canes remain toxic for up to 3 years, so beware! If an adventurer has accidentally ingested this plant, symptoms can appear anywhere from 30 minutes to a few hours. They will have the following symptoms: pupil dilation, dizziness, trembling, slow of heartbeat, central nervous system paralysis, muscle paralysis, and death from respiratory failure. Like stated previously, this plant affects animals as well, and their symptoms are: nervous trembling, salivation, lack of coordination, pupil dilation, rapid weak pulse, respiratory paralysis, coma, and sometimes death. There is no known antidote for poison hemlock poisoning, but medical intervention is imperative, especially in the case of respiratory failure or seizures. Keep a keen eye on your furry friend and don't let him or her eat anything you can't identify.

Water Hemlock - Cicuta douglasii

Identifying features: The water hemlock plant ​​ranges from 1-3 feet in height and has small white flowers similar to poison hemlock: shaped in an umbel. Leaves of this plant are key in identification. They grow alternate from each other, are pinnate (meaning they are shaped like a long feather), and are sharply toothed. A key identification tool to remember is that the leaf veins end at the bottom of the serrations instead of the top like most other plants.

Where it is commonly found: Water hemlock is found near wet seepage areas of meadows, pastures, and nearby streams. Take extreme caution in these areas and avoid this plant at all costs.

Symptoms and treatment: This is the most violently lethal plant to grow in the United States, with it having a poison (cicutoxin) that directly attacks the central nervous system. The following symptoms will occur if this plant is ingested: nervousness, excessive salivation and frothing, muscle twitching, pupil dilation, rapid pulse and breathing, tremors, violent convulsions, grand mal seizures, coma, death (can occur as early as 15 minutes after a lethal dose is consumed). Like poison hemlock, there is no antidote or cure, but treatment consists of supportive care such as IV fluids, ventilatory support, and benzodiazepines for seizures.

If any of the above plants are ingested/brushed against, seek out medical assistance as soon as possible, especially with poison and water hemlock! It’s always a smart idea to bring along a first-aid kit as well when out and about, and don’t forget to pack some Benadryl tablets and cream to relieve the effects of stinging nettle and poison oak. Just remember to stay safe, be vigilant, and keep a sharp eye out for these toxic plants!

Click on this link to learn more about other invasive and noxious plants found in the Truckee Meadows area.


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