11 Poisonous Plants to Avoid on Hikes and Outdoors

Published on 07/16/2023 · 8 min readIn this guide, Camping & Hiking Expert Jessica LaPolla shares the most commonly encountered poisonous plants to avoid outdoors so that you know what to look out for while hiking.
Jessica LaPolla, Camping Expert
By Camping Expert Jessica LaPolla

Photo by Ann Baldwin

One of the most beautiful aspects of a hike along backcountry trails is being surrounded by Nature and its abundance of diverse and interesting flora. What is not so fun is brushing up against a poisonous plant or mistaking toxic wild berries for edible ones. In this guide, we will examine some of the most commonly encountered poisonous plants so that you know what to look out for while hiking. Remember, if you think you have come into contact with, or ingested, a poisonous plant, call the poison control center immediately. Many edible-looking berries and mushrooms are toxic, so bring your own snacks with you while hiking and camping, and don't rely on Nature's pantry.

1. Poison Ivy (Toxicodendron radicans)

Photo by David Beaulieu

This common eastern North American plant ranges from green to reddish in color, depending on the season. Most people who come into contact with poison ivy develop an itchy, irritating, and sometimes painful rash caused by urushiol, a compound in the plant’s sap. Though the color and appearance of poison ivy can change, you can usually pick it out based on its almond-shaped leaves, usually grouped in threes. You may have even heard the saying “Leaves of three, leave it be”. If you come across a plant that you think might resemble poison ivy, it is best to avoid it entirely, just in case.

2. Poison Oak (Toxicodendron diversilobum)

Photo by James Whitney

This member of the sumac family inhabits much of western North America, appearing as a woody vine or low shrub-like plant. Poison oak is variable in size and appearance, sometimes growing upwards of 100 feet long as an ivy vine, or developing as dense thickets. They range from yellow-green to red, depending on the season, and similarly to poison ivy, appear in leaves of three. Unlike the smooth almond shape of poison ivy leaves, however, poison oak leaves are scalloped on the edges. People who encounter poison oak may experience itching and skin irritation, and an allergic reaction may cause the symptoms to be even more severe, so watch your step while hiking and be careful setting up camp in the backcountry.

Pro Tip: Pack small, lightweight packets of hydrocortisone cream or calamine lotion in your backpack or first aid kit. It will help relieve itching and rash caused by poison ivy.

3. Poison Sumac (Toxicodendron vernix)

Photo by Carol Dembinsky

This woody shrub can grow up to 30ft tall and grows primarily in wet, clay soils. You can find poison sumac in the eastern United States and southeastern Canada. The leaves of poison sumac are green and can have a reddish tint and are oval-shaped with sharply tapered ends. They can also have greenish flowers and clusters of white fruits. Poison sumac is more toxic than poison ivy and poison oak, with itching and irritation lasting longer in most cases, and possible swelling and recurrent eruptions of the itchy rash. Burning poison sumac can be extremely dangerous, as exposure to or inhaling the smoke can lead to pulmonary edema, so be careful when gathering wood or kindling for a fire.

4. Stinging Nettle (Urtica dioica)

Photo by Paul Morley

Stinging nettle, also known as common nettle, is an herbaceous perennial flowering plant that grows tall in the summer and becomes small and low to the ground in the winter. It can be found all over the world and has several subspecies, most of which have stinging trichomes on the leaves and stems. Stinging nettle has been used for its medicinal properties for centuries, but their stingers (which look like tiny hairs on the leaves) inject histamine and other chemicals when caught on the skin, causing a stinging and burning sensation and inflammation. The leaves are soft and green and appear to be serrated on the edges and the plant has small green-brown flowers. Stinging nettle is mostly found in meadows and pastures, so stay on the trail and don’t wander into tall grassy areas, and if you do, be sure to wear close-toed shoes/boots, long pants, and a long-sleeve top to protect your skin.

5. Poison Hemlock (Conium maculatum)

Photo by Alex Stepanov

This extremely poisonous herbaceous flowering plant is native to Europe and North Africa but has made its way to many other parts of the world, including North and South America. Poison hemlock is a member of the carrot family, but if these plants are eaten or ingested, they can cause death. All parts of the plant are toxic, and even physical contact and inhalation can have negative effects on both humans and animals. Hemlock can grow up to 12ft high and typically presents as green with purple spots. Depending on its age, it may produce white flowers in umbrella-shaped clusters. Ingestion of the toxin, even in small doses, can lead to coma or death. It is vital if you come into contact with poison hemlock to seek medical attention immediately.

6. Snowberry (Symphoricarpos)

Photo by Monika Fuchs

This resilient plant is native to North and Central America and grows primarily in forested areas. Snowberry plants have green leaves and small green-pink flowers. The plant gets its name from the snow-white berries that grow in clusters along the stem. Though snowberries are an important staple for some bird species, they are toxic to humans, and ingesting the berries can cause an upset stomach, nausea, diarrhea, vomiting, and dizziness.

7. Buttercups (Ranunculus)

Photo by Wikimedia Commons

There are about 600 species of buttercups and all of them are poisonous. They can be found in many parts of the world, including Northern Europe and North America. Buttercups can be found in pastures, meadows, and on roadsides. Most species of buttercups are perennial and will bloom in the spring, sprouting those dainty yellow petals we are all so familiar with. You can hold a buttercup under your chin to see if you like butter but refrain from ingesting these little yellow flowers. Eating them can cause blisters and dermatitis in and around the mouth and tongue.

8. Manchineel (Hippomane mancinella)

Photo by Hans Hillewaerth

This toxic tree can be found in southern North America and South America. It boasts the Spanish name “manzanilla de la muerte,” translating to “little apple of death.” Manchineel is one of the most toxic trees in the world, with every part of the tree containing a poisonous sap that can cause blistering of the skin upon contact. These trees can grow up to 50ft tall and produce green apple-like fruits, which is where they get their name from. All parts of this tree, including the fruit, flowers, leaves, and bark, are poisonous to touch and can be fatal if ingested, so if you see one of these trees, give it a wide berth.

9. Deadly Nightshade (Atropa belladonna)

Photo by Bob Gibbons

Another common name for this toxic plant is belladonna, derived from its scientific name. This plant can grow up to 7ft tall and has small, purple, bell-shaped flowers. Though the nightshade family includes delicious and edible foods like tomatoes and potatoes, belladonna is very dangerous if ingested. The foliage and berries both contain tropane alkaloids, which can cause severe symptoms including sensitivity to light, dilation of the pupils, vomiting, blurred vision, hallucinations, convulsions, or even death. Deadly nightshade is also poisonous to pets.

10. Pokeweed (Phytolacca americana)

Photo by Dave Taft

Pokeweed or “Dragonberry” is a poisonous plant that is native throughout most of the United States and can also be found in parts of Europe and Asia. It can grow up to 8ft tall and has green leaves on a green or red-purple stem. Pokeweed flowers can range from green to white and are accompanied by dark purple, almost black berries in large clusters. The entire plant is toxic, including the juicy-looking berries. If ingested, pokeweed can cause stomach pain, vomiting, and paralysis of respiratory organs. Juice from the berries can permeate skin and cause symptoms as well, so avoid touching them altogether.

11. Bittersweet (Solanum dulcamara)

Photo by Dave Taft

This plant, which can look like a small tree, is also in the nightshade family. Though not as toxic as belladonna, it can cause adverse reactions and, in some cases, death if ingested. Bittersweet is an invasive plant that has become common in many parts of the world, including North America. They can grow up to 12ft high and have green leaves with star-shaped purple flowers and red berries. They can grow nearly anywhere, and in the Middle Ages, it was thought that Bittersweet could ward off witchcraft.

Stay safe out on the trails! This list is not all-inclusive, and there are many other poisonous plants to avoid outdoors that you should keep an eye out for. Lily of the valley, rhododendrons, azaleas and even a plant as common as daffodils are toxic to humans. If you hike a lot, consider taking educational classes or workshops to dive even deeper into learning the basic skills to identify poisonous plants. Becoming familiar with your local landscape and knowing what native plants you may encounter on your local trails can save your life!

As you're preparing for your next adventure exploring the beauty of nature, if you have any questions on choosing the right gear, please feel free to reach out to me or one of my fellow Camping & Hiking Experts here at Curated for free, personalized advice and recommendations.

Curated experts can help

Have a question about the article you just read or want personal recommendations? Connect with a Curated expert and get free recommendations for whatever you’re looking for!

Read next

New and Noteworthy