Most Toxic Plants in Ohio

There’s nothing better than walking along a trail in the early Summer of Ohio when all the wildflowers are blooming and the trees are starting to regain their green foliage. You may pick some harmless dandelions as you walk along or try to find a four leaf clover from amongst millions of different clovers on the ground. Most plants found in Ohio’s numerous woodlands, fields, marshes, and parks are not going to kill you. Some people may experience allergic reactions or skin rashes when they come into contact with certain plants, but most aren’t deadly to handle. However, if your going to consume a plant it might be an entirely different story. Below are some of the most toxic plants found in Ohio with most of the plants causing harm to people when they either touch or consume the plant.

Hogweed is a tall plant with white umbrella leaves that slightly resemble Queen Annes Lace has invaded Ohio by crowding out native plants in the rich, moist soil that it favors. I first heard about the problem hogweed was causing last year when I picked up a brochure on it at a local festival. Its a threat to local ecosystems and human health because it takes over native areas quickly due to the 20,000 seeds it produces every growing season. As for human health, the furocoumarins chemicals found in the white sap can cause severe burns, scars, and temporary and even permanent blindness when it comes in contact with skin or eyes. It is a native of the Eurasia area, but escaped into Europe and then into the United States. It is a biennial herbaceous dicot and is tolerate of even the coldest climates. It can grow to 15 feet tall and has been planted for ornamental purposes.

Poison Hemlock is a poisonous member of the Umbrellacea family, which Hogweed and Queen Anne’s Lace are both relatives of. It can grow up to 7 feet tall and due to its hardiness it can survive in many different soil types. Abandoned fields, roadsides, and wet soils are all good places for Poison Hemlock to grow. It has branching white lacey flowers that come out in the shape of a slight umbrella with finely-divided, green leaves coming off of a waxy, hollow stem. It has been planted in many areas as an ornamental despite its severe toxicity to humans and animals. It has a strong noxious smell that is not pleasant to be near.

Poison Sumac, a perennial, is a highly toxic plant that often grows as a deciduous shrub or vine with alternating leaves. Its typically found growing in really wet areas and near the ground with the small yellowish green flowers blooming in July. The woody stem is a smooth light grey with branching twigs of orange-brown and red leaves that give it a rather bright color in the Summer. I have only seen this once in the woods near where I live though its relative Poison ivy is far more common. To many people this plant is highly poisonous though some may be immune just like some people don’t react to poison ivy.

Jimson Weed is a tall annual plant with pale green stems and white flowers that bloom in the Summer. The flower of Jimson weed is unique as it usually opens up at night and closes during the early part of the day. After the flower blooms it will die and be replaced with a hardy, spiny fruit that carries the seeds to grow a new generation of jimson weed. Usually these seeds will germinate in a sunny location with rich soil that contains high nitrogen content as the continuous blooming nature of jimson weed makes it necessary to have a good supply of nitrogen. Though this plant can be seen through fields and waste areas of the mid-western United States. You should never consume jimson weed as it can cause vomiting, rapid heartbeats, hallucinations, and severely poison kids. All parts are poisonous.

Oleander is a poisonous perennial plant that grows in Ohio. It has smooth, thin leaves with red-purple flowers that bloom throughout the Summer and produces seeds in the Fall. It loves the sun and can tolerate drought as the plant isn’t picky about where it grows. It grows rapidly in open fields, waste areas, and parks. And all parts of the plant are highly toxic to humans and life-stock animals.

Remember to always properly identify a plant before touching or consuming it. A good plant reference book or knowledgeable guide should be brought along whenever you are foraging for wild plants. The list above does NOT include all the toxic plants that can be found in Ohio so make sure to check other sources, too.