12 Poisonous Plants in Illinois to Stay Far Away From

Poisonous plants in Illinois can cause harm to humans and animals if proper precautions are not taken. To avoid coming into contact with these plants it is important to know which plants in Illinois are poisonous or toxic. In this article, we have given a list of various toxic plants found in Illinois.

As you keep reading this article you will learn so much about the plants that you should be staying away from, so now, check out these plants below with each of their specifications.

Various Types of Poisonous Plants in Illinois

1. Poison Hemlock

Poison hemlock or Conium Maculatum is a lethal poisonous plant that is found in Illinois and presents an extreme danger to humans and animals at the same time. These are plants that have a smooth, bluish-green mottled stems and compound leaflets with serrated edges, as well as small white flowers.

Note that every single parts of the plant are considered hazardous and can cause serious effects whenever they are ingested or any contact occurs through skin irritation or burning of mucous membranes, it is that severe. 

Symptoms of poison hemlock exposure include nausea, vomiting, confusion, muscle twitching and weakness, and the most extreme case would be leading to paralysis occurrence. Basically,  it is important to use extreme caution when in contact with the plant, because the damage is quite agitating.

2. Stinging Nettle

Stinging nettle is a common poisonous plant found throughout the state of Illinois. It grows in lawns, gardens, riversides, and disturbed areas of all kinds as it is a wild plant. The leaves and stems of the stinging nettle contain tiny as they have little needle-like hairs around them that are responsible to release an irritating cocktail of chemicals upon contact with human skin.

These chemicals would spread and give and itch, as it would welt and develop on the exposed areas within minutes, leading to redness and possible inflammation. Moreover, remember that stinging nettle is most often identified by its distinctive lanceolate-shaped leaves, which can vary in size depending on the season and habitat type, so that you would be aware and stay away from it. Although these plants are often considered pesky weeds, they sometimes provide nutritional benefits.

3. Poison Ivy

Poison ivy is a native perennial vine found throughout much of Illinois. It is distributed primarily by birds; however, it can also be found in areas that are wooded, grassy, disturbed, or undisturbed sites. Poison ivy has trifoliate leaves with leaflets that can have yellow to light green uneven margins; the stems and petioles are typically reddish-brown.

This is one of the most common intoxicating plants found in North America, as one should be cautious of, because all parts of this poisonous plant contain an oily allergen known as urushiol. This oil is one that would easily trigger a contact dermatitis reaction when the skin comes into contact with it. If individuals come into contact with poison Ivy they should wear gloves, long pants, and long sleeves.

4. Poison Oak

Poison oak is a common poisonous plant found in Illinois and other states, including surrounding regions. It can be identified by its distinct lobed leaves, shiny top surface, and white or pinkish underneath. Note that all parts of this tree are poisonous, as its sap is everywhere, which contains an allergenic oil called urushiol which causes severe skin irritation and red rashes with itching upon contact.

To elaborate further, you must be aware, because both the leaves of poison oak, and its stems, contain this irritating substance and can enter through direct contact or indirect contacts such as clothing or pet fur. If exposed to the plant, it is important to immediately wash the skin thoroughly, and as quickly as possible, or else the consequences will be heavy.

5. Giant Hogweed

Giant hogweed is an invasive weed native to Central Asia and the Caucasus region but has become a major problem in Illinois, as well as other parts of the United States. This perennial plant can grow to be over ten feet tall and has been known to cause severe skin irritation, blisters, and even blindness may also occur if the situation is not handled properly, and if the quantity is great.

Besides the risk, it poses to humans, Giant hogweed also threatens the environment by crowding out native plants that are food sources for wildlife, insects, and birds. With its large white flowers and jagged leaves, this poisonous plant is easy to identify and with all safety measures, to stay away from it.

6. Poison Sumac

Poison sumac is a poisonous plant native to the midwestern United States, including Illinois. It primarily grows in moist soils and can vary from shrub-like to small tree forms with light gray or reddish bark. Leaves are typically alternate and are pinnately compound with leaflets that are hairy on the undersides in addition to this, it also has white little berries that are also poisonous, and this is a way that you can distinguish the harmful plant easily.

Ingestion of poison sumac can cause serious skin reactions such as severe blistering and inflammation, therefore it is important to take the necessary precautions when outdoors in Illinois, especially during the spring when plants are actively flowering and bearing their fruit or the berry.

7. Morning Glory

Morning glory is a highly-recognizable poisonous plant native to almost all regions of North America. This plant is also found in the state of Illinois, it is often found flourishing along roadsides, in fields, and backyards during the summer months due to its ability to thrive in both dry and moist soils.

Despite its attractive flowers, morning glory contains toxic compounds which are known as the alkaloids, saponins, and glycosides these three can cause adverse reactions to the body if consumed. Symptoms of poisoning may include dizziness, diarrhea, vomiting, chest pain, and excessive salivation. To avoid illness or injury, it is recommended that citizens take proper caution when encountering this flowering vine by wearing protective clothing, and keeping children and pets away from them too. 

8. Foxgloves

Foxgloves are a common garden plant throughout Illinois. These tall, showy flowers have a range of striking colors that can add beauty to the landscape, this is one of the reasons that they are admired. However, they should be enjoyed with caution as they are highly toxic and contain several compounds that are poisonous, at the same time if ingested in large doses, they could even cause fatal consequences.

The primary active ingredient of this plant is digitoxin. Although the latter has been used as medicine to treat certain heart conditions in humans but can also be toxic if not taken under careful medical supervision. Ingestion of foxglove leaves or flowers can lead to nausea, vomiting, irregular heartbeat, and paralysis of the muscular system.

9. Azaleas

Azaleas are a popular flowering shrub found in many Illinois gardens as they add vibrancy to the area, however, despite this beauty they are also very toxic. All parts of the plant contain grayanotoxin, which can cause nausea, vomiting, dizziness, and confusion if ingested. Azaleas should be avoided by both humans and pets due to their potential to cause harm if consumed.

It’s best to keep them out of reach or away from any public areas where they can be easily accessed or touched. On another note, gardening gloves should also be worn when applying fertilizer or planting azaleas as contact with the skin may irritate.

10. Daffodil

Native to Europe, the Daffodil is a highly toxic plant that belongs to the Amaryllidaceae family. While prized for its sweet scent and bright yellow and white hues, this perennial flowering bulb is considered poisonous throughout most of the state of Illinois when eaten by humans or animals.

When ingested, it can cause different symptoms such as nausea, vomiting, abdominal pain, stomach cramping as well as drops in blood pressure. Furthermore, contact with this plant’s sap may also cause skin irritation and rashes, just by a single touch. Therefore, it is important to keep a close eye on children and pets if you have this type of flower in your yard.

11. Rosary Pea

Rosary pea is a poisonous plant native to subtropical and tropical regions of the world. It is an Annual Herb in the Fabaceae family and is also known as Crab’s Eye, Indian Licorice, or Precatory Bean. In Illinois, rosary pea grows typically along roadsides, riverbanks, and other disturbed areas. All parts of this plant are toxic due to the presence of abrin, which is a highly intoxicating agent, even in the smallest quantity.

However, the seeds contain the majority of this compound and when ingested can lead to nausea, vomiting, eye swelling/redness, abdominal pain, and diarrhea, moreover, when it is ingested in a larger amount, it can even be fatal. To prevent accidental poisoning, it is advised to remove these plants carefully.

12. Larkspur

Larkspur, a genus of the buttercup family, is a highly poisonous plant found throughout Illinois. It contains a toxin known as delphinine, which can cause muscular paralysis and death if ingested in large quantities. Animals are particularly susceptible and symptoms of poisoning may include abdominal pain, cramping, difficulty breathing and swallowing, trembling, and seizures.

In addition to being toxic to livestock animals such as cows and horses, larkspur plants can also be dangerous for humans if not properly handled or even by simply consumption. It is important for any individuals living or working around the plant to take necessary precautions, and cut them out completely, so that they wouldn’t harm anyone in any way.

Conclusion

As you can see, there are different kinds of poisonous plants in Illinois some of which may be useful but most of them are usually quite dangerous. To sum up these plants:

• All parts of the plants such as poison hemlock and poison ivy have toxicity and should be avoided at all costs.

• Plants such as stinging nettles or poison oak only have toxic materials in their leaves and stems.

• Only the seeds of rosary pea contain the poisonous chemical, whether ingested in a small or a larger quantity. 

• Foxgloves are toxic but have medicinal properties and so they should be grown carefully.

Now, you have a vast knowledge of how big of a damage can be caused through ingesting or even coming close to and touching these plants, which means that you must do your best and try to avoid growing these plants in your backyard unless necessary. Be mindful of how they look like, and avoid any contact, and keep children and even pets away from them too.

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