What to Watch for Before Encountering These Plants
There are many things in nature that can take you down. Most threats are obvious, such as two- and four-legged predators, storms and falling off a cliff. Then, there are the less-obvious hazards in the form of insects, bad water and even toxic plants.
In this piece, I will list and cover eight toxic plants that, if they don’t kill you, will certainly ruin your day. Learning how to identify these plants and treating the effects if you do come in contact with them are extremely important for your health and safety.
Some of these plants might be familiar to you; others might not. Several occur naturally in our environment. Others are species introduced here from other parts of the world and that have gone “wild” in our environment. A handful excrete toxins that cause topical distress, while others have to be ingested to be harmful. Some plants have both “good” and “bad” parts. All are worth learning and knowing about — and avoiding whenever possible.
The plants discussed in this section are the ones that cause skin problems when you come in contact with them. Some of these problems are simple rashes, discomfort or mild skin irritation for most people. However, they can be more serious for some people. In some cases, these poisons can become systemic, meaning that they get into your system and flare up anytime. These cases need to be treated professionally, usually with steroids.
Poison Ivy. Within this group, poison ivy is the most widely dispersed plant, and it is probably the most recognizable. Poison ivy is found throughout the United States from coast to coast and north to south. In some areas, poison ivy can be found as a low-growing shrub, while in others, it is a tree-climbing vine.
“IN SOME CASES, THESE POISONS CAN BECOME SYSTEMIC, MEANING THAT THEY GET INTO YOUR SYSTEM AND FLARE UP ANYTIME. THESE CASES NEED TO BE TREATED PROFESSIONALLY, USUALLY WITH STEROIDS.”
While the leaves might look a bit different — again, depending upon the area — all poison ivy plants have some common traits. First, the leaves form in clusters of three. The old saying, “Leaves of three, let them be” is a good way to remember to avoid these plants. Poison ivy also has green berries in the spring that turn white in the summer.
Poison ivy can be found growing just about anywhere, from deep woods to hardscrabble roadsides. Stone walls and areas around old building foundations are hotbeds for this plant.
What makes these plants toxic is an oily fluid called urushiol, which sticks to skin, clothing or fur and causes an allergic response within anywhere from five minutes to two hours after contact. There are a few ways to become exposed to the oil. First, there is direct contact with broken leaves or stems. The second way is indirect contact, such as when you touch something that has the oil on it (a tool or pet, for example). The third method is through airborne exposure, usually caused by the smoke from burning plants. This is, by far, the most dangerous — and could be fatal. Symptoms include redness, swelling, blistering and itching, with any of these ranging from mild to severe.
Poison Oak. Poison oak is closely related to poison ivy and, like poison ivy, has “leaves of three.” Unlike poison ivy, it is not widespread and is not commonly found in the northern half of the country, although there are always exceptions to the rule. It is common along the south Atlantic states and the Gulf and Pacific states east to the Rocky Mountains. Poison oak is most commonly found growing as both a low and high shrub. Within the range described above, there is no limit to where this plant can be found. Leaves often resemble the lobed leaves of an oak, hence its name.
“ONE CARELESS MISTAKE, SUCH AS THROWING A LOG WRAPPED WITH A POISON IVY VINE ONTO THE FIRE, CAN BE A POTENTIALLY LIFETHREATENING MOVE. AND BUSHWHACKING THROUGH A GROWTH OF HOGWEED COULD LEAD TO SERIOUS HEALTH CONSEQUENCES.”
Symptoms of exposure to poison oak, and the treatment of such, are exactly the same as for poison ivy. The best thing to do is avoid contact with them if possible. If you are working in an area with either plant, wear gloves, being careful how you handle them later, and avoid direct skin contact.
Poison Sumac. Poison sumac grows as a large shrub or small tree. It is found mainly in peat bogs and swampy areas in the eastern part of the United States from New England to the Gulf Coast. It is recognized by its cluster of seven to 13 smooth-edged leaves that come to a sharp point.
While this plant’s leaves are not toxic, its berries are. The berries are white and form between the leaves and the branch. This makes it almost impossible to avoid the toxin, especially if you find yourself in the thick of them.
If you come into contact with poison sumac, treat yourself just as you would after poison oak or poison ivy contact: Wash your hands and clothes and treat the symptoms. In all cases, seek medical attention if the symptoms worsen or if the rash spreads to your mouth, eyes or genitals.
Giant Hogweed. Originally introduced to the United States in the early 20th century as an ornamental garden plant, the giant hogweed quickly went “wild.” It is now found throughout the Northeast, Mid-Atlantic region and the Pacific Northwest. This plant is so bad that it is listed by the federal government and many state governments as a noxious weed.
“SYMPTOMS OF INGESTING MAYAPPLE CAN INCLUDE SALIVATION, VOMITING, DIARRHEA, HEADACHE, FEVER AND COMA. THIS TOXIN CAN CAUSE DEATH.”
Giant hogweed is easily recognized by its sheer size, which ranges between 7 and 14 feet in height. The flowers are white and form huge, umbrella-shaped clusters. The leaves are very large and deeply lobed. Stems are covered with coarse hairs that are obvious.
The sap of the giant hogweed causes severe skin and eye irritation, painful blisters, permanent scarring and even blindness. You’ll get the sap on you by brushing up against the bristles on the stem or by breaking the stem or the leaves. For this reason, it is highly recommended that you don’t touch this plant. If you suspect you have found a giant hogweed, contact your state environmental resources.
If you do come into contact with this plant, immediately wash the affected area with soap and water. Stay out of sunlight for 48 hours, because its toxin prevents your skin from protecting itself from sunlight. If symptoms still occur, you need to contact your physician immediately.
There are many plants that are toxic if ingested, and for that reason, there is a rule of thumb that should be followed: Don’t eat it unless you know for sure it is safe! If you do eat a potentially toxic plant, seek medical attention immediately. Some toxins are fast acting, and you might not have much time to counter their effects.
“THE BERRIES OF THE AMERICAN POKEWEED ARE EATEN BY MANY SPECIES OF BIRDS, BUT THEY ARE TOXIC TO HUMANS. THE MORE THE PLANT MATURES, THE MORE TOXIC IT GETS.”
Poison Hemlock. Despite its name, poison hemlock is not related to hemlock. However, it is related to wild carrot or Queen Anne’s lace, for which it is often mistaken. Like many others, this plant is an invasive species brought to the United States as an ornamental garden plant. It can be found throughout the United States along fence lines, in irrigation ditches and in other moist places. It is acutely toxic to both animals and humans, and all parts of the plant are poisonous.
Poison hemlock can be identified by its size, sometimes reaching 8 feet in height. The stem is green with purple blotches and is completely hairless. The flowers are white and form many umbrella-shaped clusters, which appear in the spring.
Typical symptoms in humans include dilation of the pupils, dizziness and trembling. Those are quickly followed by a slowing of the heartbeat, paralysis of the central nervous system and muscles. If left untreated, death will occur due to respiratory failure. Quick professional treatment is the only course of action.
American Pokeweed. Pokeweed is native to North America, specifically in the eastern half of the United States. It is a big shrub, growing as high as 8 feet in some areas. The flowers are green to white in the spring, and the berries are purple to almost black. The berries of the American pokeweed are eaten by many species of birds, but they are toxic to humans. The more the plant matures, the more toxic it gets. Pokeweed is commonly found growing in pastures, recently cleared areas, woodland openings, and along fence rows and stone walls.
All parts of this plant are toxic to humans, with the highest concentration of toxins found in the root. Despite this, “poke” is a traditional food in some areas. Only stems and leaves are eaten—and then only after they have been thoroughly cooked (usually three times, in fresh water each time). Children are the most vulnerable, because even a few berries can cause death. In adults, ingestion of pokeweed can lead to birth defects and other medical issues, including death.
Pokeweed toxin is slow acting in healthy adults. Vomiting usually starts within two hours. Severe reactions include vomiting, spasms and convulsions. Immediate reactions include a burning sensation in the mouth, cramps, vomiting and bloody diarrhea.
Mayapple. The mayapple is a woodland ground cover found throughout most of the eastern United States and southeastern Canada. Leaves are palmated and lobed. In the spring, this plant produces white, yellow and even red flowers. In the summer, green, yellow and red fruit appear.
“NO BOOK CAN COVER EVERYTHING, SO IF THERE IS ANY DOUBT IN YOUR MIND, YOUR BEST LINE OF DEFENSE IS ALWAYS TO AVOID THE SITUATION.”
All parts of this plant are poisonous if eaten—especially the green, or immature, fruit. Symptoms of ingesting mayapple can include salivation, vomiting, diarrhea, headache, fever and coma. This toxin can cause death. However, once the fruit has turned yellow and softened, it is safe to eat in small amounts … as long as the seeds are removed.
Oak. The oak is a large family of nut-bearing trees, and members of this family are found around the world. Although all parts of this plant are poisonous if eaten, it is the nut, or acorn, that is in question here. The flesh of the acorn—and every part of the oak, for that matter—contains a toxin called “tannic acid.” If ingested, the tannic acid can cause kidney damage and other gastrointestinal ailments. Symptoms of poisoning include a lack of appetite, depression, constipation, bloody diarrhea, blood in the urine and colic.
With that being said, acorns can be eaten and actually were a staple in the Native American diet. Before consumption, the shelled acorns need to have the tannic acid leeched out. This is done by soaking them in cold water. Once the water turns brown, dump out the water and soak the acorns again. Repeat the process until the water remains clear.
Avoidance Is Your Best Bet
It isn’t always or only the obvious threats that will take you down. One careless mistake, such as throwing a log wrapped with a poison ivy vine onto the fire, can be a potentially life-threatening move. And bushwhacking through a growth of hogweed could lead to serious health consequences. Eating the wrong thing can kill you before help can arrive.
All these dangers can be avoided by learning about the plants around you and making sure that a good plant identification book is part of your gear. Remember: No book can cover everything, so if there is any doubt in your mind, your best line of defense is always to avoid the situation.
There are many good books on plant identification. The only drawback is that there is no way that one book can cover everything, especially with all the invasive plants that are constantly being brought here. Most of the good books have pencil drawings of the plants they describe; the really good ones also have color photos.
Friend, fellow American Survival Guide contributor and foraging expert Christopher Nyerges has written numerous books on identification of edible wild plants based on his decades of experience in the outdoors and as an instructor.
Remember that books can provide guidance, but nothing can replace experience in the wild. There are many edible plants that look similar to poisonous varieties. Even with a book, it is sometimes hard to tell the difference between a dangerous or harmless plant. If in doubt, leave it alone. It is better to be safe than sorry.
Editor’s note: A version of this article first appeared in the April, 2019 print issue of American Survival Guide.