Poisonous plants in Ohio are ones that have taken a turn for the worst by multiplying over the last few years. While the state is home to some of the unique and interesting wildflowers out there, one should always be wary of the ones that can be of harm.

Poisonous Plants in Ohio

Some of which can even cause the deadliest of symptoms to the human body. To learn all about such toxic plants, just keep reading.  

Types of Toxic Plants in Ohio To Stay Away From

1. Poison Sumac

Even more allergic than ivy, oak, and poison hemlock ( conium maculatum ) are toxic sumac. Many people wonder, “is there poison sumac in Ohio?” well, you will be surprised to see just how much of it is there. 

Toxic Poison Sumac Shrubs

– Symptoms

Its oil is extremely allergenic and can result in serious skin reactions, including burning and itching. Sumac also includes urushiol in its sap that is a chemical which contains toxins when it comes across your tongue or even your skin, note that it is a more toxic chemical than poison ivy. 

On the other hand another way that it would be toxic is even through burning the plant. As you subject it to combustion, it would begin to release smoke, which can be extremely poisonous and hazardous and lead to lung damage and pulmonary edoema. However, this rarely occurs in extremely rare situations of true oral intake or breathing smoke from burned plants.

– Characteristics

Other types of ivy in Ohio like Toxic sumac, toxic ivy, poison oak, and poison hemlock are urushiol containing plants that should not be taken lightly. A few individuals are fortunate enough to be unaffected by this toxin, but approximately 90 percent of individuals will experience some sort of reaction to urushiol oil as it oxidizes. 

Simple itching to excruciatingly painful weeping blisters are examples of this. Even a fatal allergic reaction is possible in extreme circumstances. This plant is one that looks green, and it would have leaves that look oval in shape and produce little berries. There are a few plants that look like Poison Sumac, so you need to be able to identify it!

2. Horsenettle

The nightshade family of plants includes the prickly horsenettle. It grows on the sides of many roads and in many fields.

Spiny Horsenettle Plants

– Characteristics

Horsenettle is distinguished by the presence of yellowish, pointed, spiked thorns on the stems and leaves. This is the plant that has beautiful leaves that contain a toxic chemical in their sap, which is the one that gives it the toxic chemical. On the other hand, it also has beautiful white flowers that are also poisonous, they would start blooming in May and last till September. 

– Symptoms 

Horse nettle is very pervasive and difficult to eradicate. The plant is fully poisonous meaning all its part should be avoided. Any of the plant’s parts can make you sick, resulting in fever, headache, scratchy throat, nausea, vomiting, and diarrhea. Abdominal pain, circulatory, respiratory depression, or even death may result from eating the fruit.

It produces a yellow fruit that can be problematic and harmful for kids. When consumed, the entire plant can result in fever, nausea, vomiting, diarrhea, respiratory failure, and even death because it is so deadly.

3. Mirabilis Nyctagineal

North America and some of Europe are home to this kind of plant. It is a common misconception that this attracts and kills Japanese beetles, which aids in reducing insect infestation. 

Mysterious Mirabilis Nyctaginea Flowers

– Characteristics

They have also been tested and used as “trap crops,” grown in places separate from other crops and vegetables to keep pests away. These plants entice animals away before being sprayed on in small spaces. 

Although wild four o’clock plants do not hurt people, they can make people itchy and cause digestive issues if consumed. They also have flowers that look very pretty when they start to open up in spring through the end of summer.

– Symptoms

The most common cause of poisoning from the wild at four o’clock is accidental intake. Wild four-o’clock roots and seeds contain a slightly poisonous alkaloid that, if consumed by people, can have negative side effects. 

Children are especially vulnerable to this plant, because it is one that you can be curious. It can cause tummy aches, vomiting, and diarrhea. However, some sources do not consider it a hazardous species because of its low-level toxicity, whether by ingestion or through a simple touch. This toxic plant can be found in the wild in corn and soybean fields, meadows, grasslands, roadsides, gardens, and waste areas.

4. Jimsonweed

Jimsonweed plants are invasive weeds that can ruin any garden’s aesthetic appeal and are also members of the nightshade family. Jimsonweed is used medicinally as a painkiller, cough suppressant, and asthma therapy and as a result, it is currently being abused as a recreational drug. 

Dangerous Jimsonweed Weeds

– Symptoms

When one gets to ingest this plant, they will start to feel different effects and get intoxicated, according to the dose that they have consumed. The symptoms would include feeling being excessively thirsty, and nauseous, having urinary issues, feeling mentally unstable, and when the dose is excessive, it would even lead to a coma and even death. 

Hyoscyamine, scopolamine, and atropine are among the several alkaloids that are abundant in the plant and its seeds. Since it might have harmful effects that are both severe and immediate, it should never be taken by mouth.

– Characteristics

A sizable annual weed called jimsonweed is prone to growing in neglected areas of gardens, vegetable fields, and close to open compost or manure heaps. Moreover, as the plant is a  poisonous one, despite its unfavorable reputation, jimsonweed is neither particularly invasive nor difficult to manage, if you see it and would wish to protect people and animals from being intoxicated. It’s important to get rid of it before it produces spiky seed pods.

5. Wild Parsnip

It is exceedingly unsafe and dangerous to contact wild parsnip because it is deadly. Walking outdoors, whether in parks, on trails, or even along roadsides, requires caution.

Prickly Wild Parsnip Plants

– Characteristics

Parsnips can be recognized by its yellow, trumpet-shaped blooms and saw tooth-edged leaves. Their little yellow flowers would look beautiful in fields, however, they also contain the intoxicating sap. Moreover, the stems of these flowers would also grow in a harmonious way, being tall and green, but again, they also have an intoxicating agent.

– Symptoms

Contact with it has the potential to result in significant skin irritability and sunburn, both of which can leave a permanent scar. After accidentally ingesting this plant, it may also result in blistering or scarring when exposed to sunlight.

To elaborate further, remember that the injured skin reddens and feels tanned in mild cases, it is possible to mistake poison ivy for parsnip burns. In more severe cases, blisters appear after the skin reddens. The affected area and blisters may cause a stinging, burning, or sensation like a mild to severe sunburn.

6. Japanese Yew 

Although the Japanese yew’s magnificent red berries and brilliant yellow blossoms make for cheery holiday decorations, the plant and its seeds are extremely dangerous and should not be consumed. 

Poisonous Japanese Yew Trees

– Characteristics

These are beautiful plants that grow as tall as 30 feet tall and as wide as 15 feet. They are ones that would survive for a great number of years, although they have a slow rate when they are growing. They grow little red berries and yellow flowers that would bloom up and look stunning, in addition, their leaves have a spiky look that resemble ones of oaks.

– Symptoms

The yew tree is one of the most toxic plants, along with a closely related species popular among gardeners, the Japanese yew. All parts of the tree, except the fleshy red part of the berry, contain lethal levels of toxins that have a poisonous alkaloid found in the leaves.

They are extremely harmful to people and all animals. If someone unintentionally consumes them, they need to seek emergency medical attention since they contain taxine A and B toxins, which can lead to heart failure.

7. Polygala Senega 

Native to North and East America, where it is commonly cultivated, is Seneca snakeroot. Because it has numerous medical uses, it is mostly grown for its root. 

Unique Polygala Senega Flowers

– Characteristics

When this plant is growing, they produce beautiful stems that have a long shape, and they also produce tiny flowers at the very top of them. These little flowers would grow together in a vertical arrangement and would thrive together giving the leaves a beautiful featured characteristic. Although it is one that kids would feel attempted pick, however, all parts of this plant is filled with toxins.

– Symptoms

Small doses of the plant are not hazardous, but excessive doses can result in poisoning, which causes nausea, vomiting, and stomach discomfort.

  1. polygala senega Large doses of the plant’s toxin render victims violently puking and vomiting. Reported to have brought on nausea, dizziness, and anxiety. It really has been classified as one of the most toxic plants out there. 


Whether you’re visiting Ohio or permanently living there, it is good to know of such plants that you most definitely should stay away from.

Just remember the points that w covered: 

  • Poisonous plants in northeast Ohio like ivy and sumac can be easily in contact with humans. Make sure to keep a look out for both varieties.
  • Wild parsnips are especially common to see if you’re particularly outdoorsy. Walks, hikes, trails, and sideways will most likely have these vicious plants. No wonder it is known as wild parsnip Ohio.
  • Horsenettle plants are extremely deadly from every part. You should beware of touching it anywhere.

Now, you can be safer knowing that most of these toxic plants are identifiable by you. You can also check the most common poisonous plants in Oregon.

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