Have you ever found yourself out hiking on a narrow trail where you are constantly brushing up against plants, or you’re looking for a nice spot to set up for a picnic, and you realize that you don’t recognize half the plants around you? What if they’re poisonous?
Growing up I spent a lot of time outside (with very limited botanical knowledge) and as a result I fell victim to poison oak rashes and stinging nettle welts on more than one occasion. To help you avoid my fate on your next outdoor excursion I have put together a short list of some common poisonous plants you will come across hiking in the great state of Tennessee. Enjoy!
Poison Ivy
Poison ivy (Toxicodendron radicans) is infamous on the East Coast, but some people still struggle to identify it because of its plain looks. When the plant’s leaves, stems or roots make contact with skin, it leaves behind a red itchy rash that can last for weeks if not treated properly. This reaction is due to an oil the plant produces called urushiol. For identification of the rash and treatment options visit this page by the Mayo Clinic. Poison ivy can be identified by its three-leaf formation growing off of a main vine. It can be found growing on the ground but the plant likes to slither its way up tree trunks as well.
The leaves change color depending on the season. In the Spring they may appear red or red/green. Come Summer many of the leaves will have turned green, but new growth on the plant will be red. There may be small bunches of white-ish berries present as well. In the Fall poison ivy will take on Fall colors, with leaves turning either red, yellow, or orange. Winter is arguably when poison ivy is the most difficult to identify and avoid, because the red leaves will eventually shrivel away and fall off, leaving only the roots and stems exposed.
Unfortunately these parts of the plant can still give you a rash. Personally I have not been around poison ivy or gotten its oil on my skin, but from what I have read and heard the rash is similar to that of poison oak.
Stinging Nettle
Stinging nettle (Urtica dioica) is found across most of North America. Growing up in Northern California I came across the plant frequently while hiking, especially alongside creeks and rivers. I brushed against it on one occasion and within minutes felt an acute stinging sensation on my hand and wrist. Within the hour hives appeared and covered the affected area. Luckily for me, the rash this plant produces generally only lasts a day before fading away.
For information on how to identify and treat a stinging nettle rash, go to healthline.com. Stinging nettle can grow in a variety of habitats, but it prefers damp fertile ground (hence me finding them growing along streams). The plants generally grow to waist height but in some cases can reach 9 feet off the ground. The leaves and hairs on stinging nettle are its most identifiable features. The leaves grow opposite each other, and have saw-tooth edges. The leaves are always green but can vary in shade of color. Look for the tiny hairs that are found on the stems and leaves of stinging nettle. These hairs when touched will stick into the skin and cause irritation, stinging, and hives. For a detailed look at identifying stinging nettle, visit this page.
Poison Sumac
Poison sumac (Toxicodendron vernix) has the same oil found in poison ivy and poison oak, urushiol. When it makes contact with the skin it causes irritation and itching. Click here for more information on how to identify and treat a rash from it. The leaves have smooth edges, and grow opposite one another up the stem until coming to a point with a single leaf at the end. For most of the year the leaves will be green with a yellow centerline, while in the Fall they will turn either yellow, orange or red.
The stems of poison sumac take on a light red color, making the plant stand out from many others. Green berries will appear starting in the Spring and continuing through the Summer months, shifting to an off-white color in the Fall. Poison sumac is a shrub, and can grow to be anywhere from 6-20 feet off the ground. The bark is light brown and will be fairly smooth when the tree is young, but older bark will take on a rougher texture and slightly darker color.
This site has descriptions and close-up pictures of the various identifying features of poison sumac, so I recommend you check it out before your next outdoor excursion in Tennessee.
Poison Oak
Poison oak may look harmless if you don’t know what you’re looking for, but trust me you do not want to touch this plant. I got a poison oak rash on my leg when I was around 12 years old, and it took me weeks to get rid of. The itching is a constant annoyance and scratching only makes matters worse, so keep your eyes peeled and wear long pants whenever you’re out hiking. For rash treatment visit this page.
Poison oak, much like its cousin poison ivy, can be identified by its signature three leaf clusters. Unlike poison ivy, the leaves have a more rounded, lobed shape, and grow tiny hairs. On the East Coast poison oak grows as a shrub and can reach 3 feet off the ground. The plant contains the same oil mentioned earlier, urushiol, and touching the leaves, stems, or any part of the plant can give you a rash.
The leaves and stems of poison oak will often appear oily and may shine in the sun, making it easier to identify and avoid. In the Spring and Summer months the leaves will be green, but come Fall they will change to orange or red. In the Winter months leaves will fall off leaving only the stems and making poison oak difficult to spot. Here is a good video giving you a better size reference of the plant.
Poison Hemlock
Poison hemlock can be found across the United States. It is a weed and a member of the carrot family, so it has become abundant in some areas and a menace to humans and livestock. Ingesting the plant is deadly, but even touching it can release toxins into your bloodstream and attack your nervous system. If you think you have come into contact with this plant call poison control at 1-800-222-1222 or 911. For more details on the plant and its toxins visit this page.
The leaves of poison hemlock resemble that of ferns with many teeth lining the edges. The leaves and stems are green, but the stems are often speckled with red or purple spots. Small white flowers grow in clusters at the top of the stalks. The plants can be short, but when they mature they can reach up to 10 feet in height. People can mistake them for wild carrots, so if you are out foraging I recommend steering clear of carrots unless you are experienced and highly knowledgeable in botany. Visit Ohio State’s Weed Guide for information and close-up images of poison hemlocks identifying features.
Hopefully this article doesn’t deter you from going out on your next outdoor adventure. It is only meant to give you the tools to identify plants along the way that could ruin your day, but now that you know what they look like you should be all set to step into nature with confidence. I hope that you enjoyed learning about all of these interesting (albeit dangerous) plants, now go grab some friends and get outside!
