16 Poisonous Plants to Avoid in Kentucky

Written by Telea Dodge
Updated: July 13, 2023
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Kentucky is a beautiful place to explore, from its western mountain ranges to its coastal plains, but it is important to be aware of potential dangers while visiting the Bluegrass State. This article explores 16 poisonous plants that grow in Kentucky and will explain what they look like, where they grow, and what happens when humans and animals come into contact with them.

What is a Poisonous Plant?

A rectangular wooden sign, painted brown with white letters spelling out poison ivy. The sign appears to be smack-dab in the middle of a wild-looking patch of poison ivy.

Pay attention to posted warnings about poisonous plants.

©Tim R7/Shutterstock.com

A poisonous plant is any plant that, when touched or ingested in a large enough quantity, can deal harm or death to any organism. So, any plant that causes a toxic or fatal reaction in a living creature. These plants do not always cause severe reactions – some poisons are mild with short recovery times. There are thousands of poisonous plants worldwide, and there are over 500 species that grow in the United States alone. There are nearly 100 potentially poisonous plants in Kentucky, but not all of them impact humans. Let’s take a look at 16 of them.

1. Mountain Laurel (Kalmia latifolia)

Mountain Laurel Blooming in the Appalachian Spring

Laurels bloom in Kentucky from May to July.

©rck_953/Shutterstock.com

The mountain laurel is one of several laurel varieties in the world. All laurels, with the exception of the Bay laurel (Laurus nobilis), are poisonous. This particular laurel is an evergreen shrub that grows in the higher elevations of Kentucky and thrives in highly acidic soil. Because of this, mountainous forest areas – especially ones made up of coniferous trees – are a perfect environment for it. In low-lying areas with moist soil, it forms in dense thickets, while at higher elevations it grows in sparse patches. In its blooming season, the mountain laurel flowers prodigiously, in hues of white, pink, and purple.

All parts of this plant are poisonous and sometimes deadly. Ingestion by humans, goats, cattle, monkeys, horses, and deer results in a variety of symptoms, such as profuse salivation, trouble breathing, vomiting, convulsions, weakness, cardiac distress, depression, paralysis, coma, and death. Initial ingestion in humans causes burning on the lips, followed by more severe symptoms six or more hours later.

2. Poison Ivy (Toxicodendron radicans)

Poison ivy

Poison ivy is recognized by its 3 distinct leaves, explaining the common warning rhyme, “Leaves of three, let it be.”

©Tim Mainiero/Shutterstock.com

Perhaps one of the most familiar poisonous plants on this list, poison ivy is actually descriptive of three separate species that share similar characteristics and toxicity. Two of these species grow in the United States and one in East Asia. In Kentucky, this allergenic plant grows everywhere. It grows as a small plant, climbing vine, or shrub. Contrary to its name, poison ivy is not a part of the ivy family. Instead, it is a member of the cashew and pistachio family.

While all parts of the plant are poisonous, it only has an effect on humans. In fact, there are several species of animals, such as squirrels, goats, and turkeys, that eat the leaves or consume the berries. Contact with any part of the plant is potentially dangerous to the skin. In affected individuals, the oils from the plant soak into the skin and cause a reaction. Failure to wash these oils away swiftly (within 15 minutes) results in a rash. The poison ivy rash, depending on the severity of the reaction, presents as itchy and blistering. Treatment for more severe cases involves the use of topical steroids and antihistamines.

3. Poison Sumac (Toxicodendron vernix)

poison sumac berries on vine

It is easy to identify poison sumac by its distinct white berries.

©G_r_B/Shutterstock.com

Poison sumac is another member of the cashew family. It grows in the moist lowlands of Kentucky. This plant is a lot more rare to come across than others on this list, but it still presents a danger to humans who interact with it. The shrub fares best in highly acidic swamp-like areas. For this reason, you are most likely to find it in the cypress swamp region in western Kentucky.

Complications of skin contact include symptoms similar to that of its close relative, poison ivy. Treatment for the rash is also similar, with topical ointments being the first line of harm reduction after the rash appears. Interestingly, the oils in this plant only have an impact on around 85 percent of humans.

4. Wild Parsnip (Pastinaca sativa)

Wild parsnip with leaves displayed

While the stems, leaves, and flowers are all highly toxic, the ripe roots of wild parsnips are edible.

©R. A. Nonenmacher / CC BY-SA 4.0 – License

Wild parsnip is another unfortunate invasive weed in Kentucky, and it is spreading uncontrollably. It thrives in both moist and dry soil, invading and dominating open habitats. It grows to heights of 4 feet, with blooms that spread up to eight inches in diameter.

This wild plant does not cause a rash, rather, a compound in its sap reacts to sunlight and causes chemical burns due to a condition called “phytophotodermatitis”. This painful rash leaves a mark – human skin remains discolored for up to two years after burns occur. Cover your skin immediately after contact with wild parsnip, do not expose it to the sun for eight or more hours, and wash the contact area with warm water and mild soap as soon as possible. There is no cure for parsnip burns, and skin discoloration and scarring remain present for up to two years after exposure incidents.

5. Poison Hemlock (Conium maculatum)

close up wild white flowers of hemlock plant

Famously, poison hemlock was used to execute prisoners in ancient Greece, including Socrates in 329 B.C.

©iStock.com/gabrielabertolini

Poison hemlock is a growing problem in all parts of Kentucky. This plant is an invasive weed from the carrot family, and it is one of the most toxic weeds in the world. Native to Europe and introduced to the United States as an ornamental plant, it has spread quickly and dangerously throughout the country. In Kentucky, it started as a roadside nuisance and quickly became a threat to the larger part of the state, spreading to moisture-rich areas and then creeping into pastures and forages.

Poison hemlock is poisonous from root to flower, and its leaves become the most toxic in the spring. It is deadly to humans and all forms of livestock, including sheep and cattle. Symptoms of poisoning by this plant include shaking, weakness in the muscles, pupillary dilation, loss of coordination, confusion, respiratory paralysis, and death. It is best to completely avoid this plant, and you should look to your local agricultural and natural resource authorities for information about how to manage its spread.

6. Baneberry (Actaea rubra)

Actaea pachypoda doll's-eyes

Doll’s eye is another name for Baneberry, due to the distinct black pupils on the white berries.

©Alex Polo/Shutterstock.com

Baneberry is everywhere in Kentucky, with a concentration around Louisville, according to community reports submitted by users on the nature-tracking app, iNaturalist. This perennial berry has red and white varieties that grow all over the United States. In Kentucky, white Baneberry is the most common and grows to heights of over two feet.

Every part of the Baneberry is toxic, but poisoning isn’t likely. The highest concentration of toxins exists in the berries, which are incredibly bitter. When ingested, dizziness, increased heart rate, and severe stomach upset occur, along with a risk of cardiac arrest. Children are particularly susceptible to the chemicals contained within the poisonous berries, and death may occur upon ingesting as few as two of the fruits.

7. Bittersweet Nightshade (Solanum dulcamara)

Bittersweet nightshade, Solanum dulcamara, flowers and buds with leaves close up.

All parts of the bittersweet nightshade are toxic to livestock, humans, and pets.

©olko1975/Shutterstock.com

Bittersweet nightshade is a member of the potato family, and grows in long, creeping vines. It is invasive to any man-made or disturbed habitat and has spread quickly through Kentucky. Despite its use in homeopathic remedies, all parts of the plant are toxic.

Fortunately, it is the most dangerous when ingested, and the bitter flavor of the red berries it produces is unpalatable to most. Regardless, experts suggest you wear gloves when handling or removing this plant, as contact with it causes skin irritation and sensitivity to sunlight in many cases.

8. Jimsonweed (Datura stramonium)

White trumpet shaped flower of hallucinogen plant Devil's Trumpet, also called Jimsonweed, latin name Datura Stramonium. Spiky seed capsule in background

‘Devil’s Snare’ is another name for this toxic member of the Nightshade family.

©weha/Shutterstock.com

Jimsomweed is another poisonous plant growing in Kentucky, most notedly in the southern part of the state. Another relative to the potato, it is highly toxic and potentially deadly. This nightshade variety has many names, including ‘thorn apple’, for the spiky and toxic fruits it grows. This plant grows up to 6.5 feet tall and has large, trumpet-like white and violet blooms during the flowering season.

Jimsomweed poisoning is fairly common, and side effects from ingestion in humans include restlessness, pupil dilation, nausea, hallucinations, and agitation. More severe cases bring convulsions and coma. There is very little danger in touching the plant, but it is important to avoid ingesting any part of it.

9. Snow-On-The-Mountain (Euphorbia marginata)

Sunny Euphorbia marginata

This poisonous plant is also known as “smoke-on-the-prairie”, and grows up to four feet in height.

©KIM JIHYUN/Shutterstock.com

Snow-on-the-mountain is a plant from the spurge family, and it is native to most of the United States, including Kentucky. It grows in 13 counties across the state, with a concentration in the north and northeast. The dicot succulent is easy to recognize and gets its name from the bright white leaves that grow near the top of each plant. It grows best in shaded areas and is both naturally occurring and ornamental for decorative gardens.

This plant is poisonous due to the milky white sap it produces, which causes a rash when it comes into contact with the skin of humans. It also causes toxicity in livestock, the side effects of which include weight gain.

10. Jack-In-The-Pulpit (Arisaema triphyllum sensu lato)

Jack-in-the-Pulpit

This herbaceous perennial is poisonous when ingested raw, but is consumed cooked as a root vegetable.

©iStock.com/MelodyanneM

Jack-in-the-pulpit is a small perennial that grows in Kentucky and is actually a set of four unique plants in the same family. The North American variety grows in heavy shade and wet soil and is hermaphroditic. In its first spring blooming, the plant grows only male flowers, but female flowers appear further down the stem as the plant reaches maturity. This is when the plant creates berries, but it takes up to five years to reach this stage. The male flowers do not pollinate the female flowers on the same plant, as they die before the female flowers are ready. This keeps the species healthy and well-bred by avoiding line pollination. The female flower is “Jill-in-the-pulpit”, and is cannibalistic to its pollinator, the fungus gnat.

Calcium oxalate, the poison in this strange plant, causes an array of symptoms when ingested by humans. These side effects include burning and blistering of the mouth, increased salivation, diarrhea, nausea and vomiting, corneal damage, and swelling of the lips, mouth, and tongue. Alleviate immediate symptoms by rinsing out the mouth and drinking milk. Make sure to call a poison control agency near you if symptoms progress or worsen.

11. White Snakeroot (Ageratina altissima)

White snakeroot

Indigenous Americans believed this plant cured snake bites, but it has killed thousands of people, including the mother of President Abraham Lincoln.

©Nahhana/Shutterstock.com

White snakeroot is another poisonous plant that is native to Kentucky. The USDA Plants Database reports that it grows in almost every county in the state, excluding a small eastern strip of coastal plains counties. This dicot grows up to 6 feet tall and produces small clusters of white blooms during flowering.

White snakeroot is poisonous to humans and livestock alike. Although the risk of poisoning is much lower now, it is still good to be wary of this plant. Ingestion in humans causes a condition called “milk sickness”, which causes sometimes fatal bouts of vomiting. In livestock and other animals, the poison causes vomiting, severe intestinal pain, and trembling. Ingesting milk or meat from animals who have eaten white snakeroot also causes illness.

12. Pokeweed (Phytolacca americana)

pokeweed berries on plant

Most pokeweed plants have shockingly pink stems, making them easy to identify.

©tamu1500/Shutterstock.com

Pokeweed is a native herbaceous species to Kentucky and North America at large. It grows in wet, sandy areas, and it is the stems, roots, and berries that make this plant poisonous. It grows aggressively, spreading quickly by seed and reaching heights of 4-10 feet. The berries contain a red dye that has many uses, including enhancing the color of wines and candies.

Pokeweed poisoning occurs upon ingestion. Children are most susceptible, as the berries are beautiful and tempting. Ingestion of any part of the raw plant causes nausea and vomiting and sometimes results in death. Livestock and horses are also vulnerable to the poison. Research shows a possibility of birth defects and cancer after human consumption. Death is most common by way of respiratory depression. Pokeweed juice absorbs through the skin, so it is best to handle this plant with gloves on.

13. Kentucky Coffeetree (Gymnocladus dioicus)

Kentucky Coffeetree Canopy Close-up in the Middle of Summer

Wood from the coffeetree was first used in the construction of railway sleeper cars.

©iStock.com/Inimma-IS

The Kentucky coffeetree gets its name from the early settlers of Kentucky, who observed a resemblance between coffee beans and the seeds it produces. Despite being poisonous, it is a well-loved member of the legume family and grows up to 70 feet high. It grows in floodplains and river valleys but is also prevalent in limestone woods. The seeds grow in large, rough, dark pods, which makes the tree easy to spot during fruiting.

The risk of poisoning from this tree is low, but humans, livestock, and pets can experience it. Cystisine, the toxin the tree produces, concentrates in the leaves, seeds, pulp, and young sprouts of this tree. Side effects of ingestion include rapid onset of muscle paralysis, vomiting, GI irritation, hypertension, and convulsion. Reports of cattle dying from drinking water contaminated by fallen leaves are not uncommon.

14. Elderberry (Sambucus nigra)

Elder Tree

Cooking the berries of this flowering plant removes the toxin that makes it poisonous.

©Juver/Shutterstock.com

Elderberry is a tree or shrub that belongs to the Sambucus family. It is a nitrogen-dependent plant and grows near farms and organic disposal sites for this reason. It is native to Kentucky, and its large clusters of dark berries are present in every county across the state.

Every part of this plant is poisonous, but the cooked juice of the fruiting berries is edible and often used as a homeopathic flu remedy. Ingestion of raw material from elderberry results in nausea, vomiting, weakness, and cramps.

15. Black Locust (Robinia pseudoacacia)

Black locust tree with white flowers

Poisonous peas? The black locust is a deadly member of the Fabaceae family, belonging to a subfamily of legumes.

©iStock.com/seven75

The black locust is a native species in Kentucky, but it is highly invasive in many other areas due to its incredible adaptability. It can grow in a wide variety of soils and conditions, and it crowds other native plants out. More importantly, it is quite toxic.

All domestic animals are vulnerable to poisoning from black locust trees, and all parts of the tree are toxic. However, it is only toxic when ingested. The spiky thorns hurt quite a bit on contact, but symptoms of poisoning occur on consumption. Livestock are particularly vulnerable, and the young shoots of the black locust tree are attractive as forage. Keep cows, chickens, sheep, horses, and children away from this fragrant foliage to prevent symptoms of black locust poisoning, such as rapid respiration, abdominal pain, muscle weakness, and dilated pupils.

16. Moonseed (Menispermum canadense)

Leafes of the Common Canada Moonseed (Menispermum canadense)

You may also recognize this plant by another name – wild grapes.

©Ole Schoener/Shutterstock.com

Moonseed is a climbing vine that grows prodigiously through Kentucky. It reaches lengths of 20 feet, and its components are deadly! This vine is hardy – when it can’t grow upwards, it creeps quickly across the ground with no limit to its length. The fruit it grows is grape-like and seeded. It flowers from May to June and begins fruiting in September.

Every part of the vine is toxic, but the danger is highest during fruiting because of the visual similarity to grapes. You can tell the difference between grape vines and moonseeds in a couple of ways. First, grape vines have tendrils while moonseed does not. Second, grape seeds are round and moonseeds are not. The crescent moon shape of this vine’s seed is where it got its name. Finally, the taste of moonseed is horrible. Ingestion of this foul fruit can be deadly, though the more common symptoms are confusion, dizziness, stomach pain, vomiting, and irregular heart rate.

Summary of Poisonous Plants in Kentucky

RankPlant NameScientific Name
1Mountain LaurelKalmia latifolia
2Poison IvyToxicodendron radicans
3Poison SumacToxicodendron vernix
4Wild ParsnipPastinaca sativa
5Poison HemlockConium maculatum
6BaneberryActaea rubra
7Bittersweet NightshadeSolanum dulcamara
8JimsonweedDatura stramonium
9Snow-On-The-MountainEuphorbia marginata
10Jack-In-The-PulpitArisaema triphyllum sensu lato
11White SnakerootAgeratina altissima
12PokeweedPhytolacca americana
13Kentucky CoffeetreeGymnocladus dioicus
14ElderberrySambucus nigra
15Black LocustRobinia pseudoacacia
16MoonseedMenispermum canadense
Summary Table of 16 Poisonous Plants to Avoid in Kentucky

The photo featured at the top of this post is © iStock.com/Werner Meidinger


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About the Author

Telea Dodge is an animal enthusiast and nature fiend with a particular interest in teaching a sense of community and compassion through interactions with the world at large. Carrying a passion for wild foraging, animal behaviorism, traveling, and music, Telea spends their free time practicing their hobbies while exploring with their companion dog, Spectre.

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