Poisonous Plants of Illinois and How to Identify Them

Guide

Mar 21

White Jimsonweed Flower with Foliage — "*Jimsonweed" by* *jmeissen* *is licensed under* *CC BY-SA 2.0*

Pretty and Dangerous

When I was younger, I would see these “mini trees” with brightly colored stems, wide, flat leaves, and berries the color of midnight. I would sometimes pick off the berries and make “potions” with them, at least until my mom told me the berries could kill me. That plant was the pokeweed, a plant we will be discussing later on in this blog post. One may wonder, “Why do poisonous plants exist? What purpose does the poison serve?” and the answer to that is a relatively simple one. Plants don’t want to get eaten, especially by certain animals.

Take the pokeweed for example. It wants its seeds to be spread by birds and it does not want it to be eaten by mammals, whose digestive system will destroy the seeds. By making the berries, along with the rest of the plant poisonous to mammals, mammals will avoid eating pokeweed and the birds can still spread the seeds of the plant! There are many toxic plants out there, but here we will be focusing on poison ivy, jimsonweed, nightshade, poison hemlock, and aforementioned pokeweed.

Poison Ivy (Toxodrendron radicans)

“Leaves of three, leave them be”. Poison ivy is a well-known and very common poisonous plant that can be found in numerous places, such as the edge of woodlands, roadsides, residential neighborhoods, forest preserves, and campsites. The “leaves of three” saying is a little inaccurate since each “leaf” is actually made up of 3 leaflets, or parts of a compound leaf . Each leaflet has a jagged edge that looks sort of like a mitten. If touched, the oils from the plant will cause a blistering allergic reaction. The oils can also affect you if the plant is burned, so don’t try to get rid of your poison ivy by burning it. Instead, try cutting it to the ground continuously in the spring, digging it up, or using herbicide.

Jimsonweed (Datura spp.)

Jimsonweed is a relative of the nightshade family, and is considered dangerous for both humans and animals. It has a white or purple trumpet flower, and a large, spiky, round seedpod. The leaves create a nasty smell when crushed as well. It tends to grow in cultivated soil, and all of it is still poisonous, both dried and fresh, so be careful when handling it. It is toxic when eaten, and its poison results in multiple symptoms such as dilated pupils restlessness, rapid and irregular breathing, a fast heart rate, twitching, and it can lead to death. The best way to remove jimsonweed if you come across it in your yard is to weed it when it is a seedling. Older plants have a large taproot which can make it difficult to remove, so it’s best to get rid of it when it’s small. You can also use certain herbicides to help get rid of it.

"*Jimsonweed seed capsule" by* *Petergray4045* *is licensed under* *CC BY-SA 4.0*

"*Silver-Leaf Nightshade (Solanum Elaeafolium)" by* *John Pavelka* *is licensed under* *CC BY 2.0*

Nightshade (Solanum spp.)

There are several different types of nightshade in Illinois, and there is a lot of variation between species. In general, they like to grow or climb as a vine. The flowers have 5 petals, and the center points away from the flower in a beak-like shape. All of the plant is considered poisonous, but the most common vector of poisoning is the berries. It grows in the northern part of Illinois among other native plant species. Muscle cramping, vomiting, headaches, and drowsiness are common symptoms of nightshade poisoning. You can remove it by hand-pulling it out of the ground.

Poison Hemlock (Conium maculatum)

Very similar to queen anne’s lace, poison hemlock has tiny, white flowers formed into widespread clusters. You can tell it apart from queen anne’s lace by the lack of a small purple flower in the center of the flower cluster. It has long, hollow branches with fern-like leaves. It also has a mottled green and purple stem, and the white taproot of this plant is often confused for carrots or parsnips. All of the plant is poisonous, so be careful. This plant has some serious poisoning symptoms, such as nausea, vomiting, confusion, drowsiness, muscle paralysis, and death. To safely remove it, use gloves when pulling it out of the ground. You can also remove it by hoeing it or spot treating it with herbicide.

Pokeberry, Pokeweed, Ink Berry — "*Pokeweed berries" by* *rkramer62* *is licensed under* *CC BY 2.0*

Pokeweed (Phytolacca americana)

Pokeweed, aka pokeberry or ink berry, can be found all over the state. It has broad, flat leaves, a bright purple-magenta stem, green-white flowers, and green berries that turn a dark purple when ripe. People have been known to use the berries as an ink or dye! Once again, all of the plant is poisonous, but if harvested very young it can be used as a food source. The symptoms of pokeweed poisoning include headaches, vomiting, sore throat, stomach pain, fever, irregular heartbeat, and it can also be deadly to young children. It is a very hard plant to remove due to its thick and strong root system. You have to dig up the plant with a shovel to fully remove the plant, and you can use certain herbicides to kill the plant as well.

Be Careful Out There

Whether it’s going through a forest preserve or your own backyard, you’re bound to find a plant that you don’t recognize. Some plants are “friendly” plants” and others are “do not touch ever” plants. Hopefully this quick guide helps you recognize some of the plants that you shouldn’t mess with.

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I would also like to thank PennState Extension, Chicago Botanic Gardens, the Illinois Department of Natural Resources, Illinois Wildflowers, University of California Agriculture & Natural Resources, and West Virginia University Extension for the information used in this blog post! If you want to check out their websites, they’re linked below.

Penn State Extension:

https://extension.psu.edu/toxic-weed-in-the-landscape-jimsonweed

Chicago Botanic Gardens:

https://www.chicagobotanic.org/plantinfo/poison_ivy

Illinois Department of Natural Resources:

https://dnr.illinois.gov/content/dam/soi/en/web/dnr/publications/documents/00000653.pdf

Illinois Wildflowers:

https://www.illinoiswildflowers.info/weeds/plants/pokeweed.htm

University of California Agriculture and Natural Resources:

https://ipm.ucanr.edu/PMG/PESTNOTES/pn74162.html

https://ipm.ucanr.edu/PMG/PESTNOTES/pn74173.html

West Virginia University Extension: