12 Poisonous Plants in Missouri People Should Avoid Planting

Poisonous plants in Missouri have toxic properties that can be dangerous to humans and animals alike. While most of these plants don’t cause serious harm, it is important to be aware of some of the more common poisonous plants in Missouri before taking a stroll outdoors.

This list contains some of the most common poisonous plants that Missourians should watch out for. Check the details of these plants below.

List of Poisonous Plants in Missouri

1. Poison Hemlock

Poison hemlock is a highly poisonous plant found in Missouri. This deciduous herb grows up to eight feet high, with hollow hairless stems and small white flowers. All parts of this plant are toxic and can cause paralysis, convulsions, and coma, of course it would depend on the quantity that one would be exposed to. 

It is not likely to cause severe illness or death when ingested in small quantities; however, even a single leaf can be fatal when eaten, which means that a single bite is harmful but not as dangerous as a full leaflet. This plant is most commonly encountered near waterways and roadsides, where it may mix with other wild plants that could potentially be mistaken for edible foliage.

2. Deadly Nightshade 

Atropa Belladonna is the scientific name for the deadly nightshade plant. It is a member of the Solanaceae family. This toxic species can be found growing wild in Missouri, typically on roadsides and in abandoned gardens, as well as areas disturbed by human activities.

It has a strong anticholinergic effect, which means that every part of the plant contains alkaloids that affect nerve function and disrupt organ system functioning, and as a result, one would start having dilated pupils, dizziness, and even a fast heart beat. The ingested berries are particularly poisonous and can lead to paralysis, coma, and death in high doses.

3. Rosary Pea

Native to tropical regions of Asia, Africa, and the Americas, the rosary pea is an annual twining vine that has been widely naturalized in warm regions around the world. Identified as a noxious weed in Missouri, this plant has likely spread by its quick-maturing nature and prolific seed production.

Poisonous when ingested, the rosary pea is exceptionally toxic because it contains abrin, which is a chemical that’s 0.1 microgram is venomous. When consumed, patients often suffer severe vomiting, abdominal pain, diarrhea, and hypotension leading them to require aggressive supportive care for up to weeks.

4. Castor Bean 

Castor bean is also known as Ricinus Communis in botany, and it is a highly toxic plant that has the potential to cause severe medical emergencies and death if ingested. Native to tropical India, it has spread throughout Missouri and is easily found in gardens and yards.

The potential danger of this plant comes from its seeds, which contain the chemical component known as ricin. This chemical is an extremely powerful poison that can lead to respiratory failure when ingested. On another note, its exposure through skin contact or inhalation can also lead to illnesses. In addition to this, even indirect exposure to castor bean plants can be hazardous.

5. White Snakeroot

White snakeroot is a common toxic plant found in Missouri, as well as in several other states across America. It contains the toxin tremetol, which can be fatal to livestock when ingested in large quantities, this is due to the fact that the human body cannot come across such a hazardous chemical.

On another note, humans can also be poisoned by consuming animals that feed on the plant. Some of the symptoms of poisoning would include nausea, vomiting, and an enlarged liver; if left untreated it can lead to death. It may reach heights of around four feet with small white flowers and fuzzy leaves.

6. Poison Ivy

Poison ivy is an extremely common poisonous plant found throughout Missouri, with its green leaves that would be much stronger in their color during summer time. This vine has trifoliate leaves, with three almond or egg-shaped leaflets of bright green color. By contact or inhalation, the chemical found in the poison ivy, which is the urushiol oil, can cause severe inflammation of the skin and respiratory system in humans and many other animals. 

This leads to burning sensations, itching, swelling of the skin, blisters, and red rashes, when it is in direct contact, as it may get even more severe. When one gets irritated, this process can last for up to two weeks if proper prevention measures are not taken.

7. Poison Oak

Poison oak is a poisonous plant found in Missouri, typically growing along wooded slopes and vines. Note that this plant has leaves that are compound, multi-divided, and arranged alternately with pointed lobes, and this is where its toxic sap is found. The foliage can range in color from green to reddish brown depending on the season and light availability, however, it is found quite in a large number.

While poison oak is often mistaken for harmless plants such as Virginia creeper, the danger of its presence lies in the urushiol oil contained within the leaves, stems, and roots which can cause intense itching and burn upon contact with the skin due to an allergic reaction.

8. Water Hemlock

Water hemlock is another highly toxic plant which is a perennial plant found in wet, marshy areas throughout Missouri, this is the type of environment it thrives in and can be located, most of the time. The species has small white flowers with five petals and compound leaves divided into leaflets, often mistaken for edible umbellifer roots such as wild carrots.

When one intends to consume this plant it would result in severe gastric upset, seizures, muscular paralysis, and even death due to cardiac arrest caused by toxins cicutoxin and cicutol. In order to avoid accidental consumption of this poisonous native Missouri species it is important to be able to recognize the leaf shape and other distinguishing characteristics, and to stay away from it, keeping all types of dangers as far as possible.

9. Foxgloves

Foxgloves are a highly toxic and potentially deadly plant that can be found growing wild in many parts of Missouri. All parts of this plant contain a powerful steroid-like glycoside toxin called digitalin, which can cause significant disturbances to the heart’s rhythm when ingested. As a result, when the heart is in trouble, the paralysis toxin would be venomous to the body, and the heart rate would shift.

Despite its toxin content, foxglove is sometimes still collected for medicinal use by unqualified individuals who may be unaware of its hazards. On another note, foxglove’s attractive flower spikes render it an appealing garden specimen to some Missourians, however, at all costs it is advised to stay away.

10. Oleander

Oleanders are toxic plants native to the Mediterranean and commonly cultivated in the state of Missouri as well. It is incredibly poisonous, containing a wide range of toxins including cardiac glycosides, which can cause serious health effects if ingested, because it will be heavy for the stomach to churn it.

While all parts of the oleander plant are dangerous, it is important to note that its flowers are particularly attractive to humans, making them a potential hazard. By the same token, any exposure to either the sap or smoke generated when burning oleander should be avoided as these have also been associated with toxicity as well as additional adverse effects.

11. Soapwort

Soapwort is a poisonous plant native to Missouri, and other parts of the United States as well. This plant is one that is highly and severely toxic when onee ingests it, containing toxic alkaloids in its stem, leaves, and flowers. However, it has historically been used as a mild soap alternative for wiping delicate items when boiled or soaked in water.

The stems contain saponines that are responsible for the soapy lather formation when agitated in water. Ingesting any part of the plant can cause vomiting, nausea, and diarrhea due to these toxins.

12. Sweet Clover

Sweet clover is a poisonous plant that is commonly found in Missouri. This plant is often mistaken for edible clovers due to the similar heart-shaped leaves, although sweet clover contains toxic compound which is called the coumarin compounds, it has the ability to cause illness when consumed by humans or even animals. It would make the layer that’s below the skin to swell up, and fill it with blood cloths, and even to result in anemia.

however, thee severe case that it can even cause would be death in cases of consumption of large quantities. Sweet clover may range in color from white to yellow and have an unmistakable odor when mature, which allows it to be easily identified and avoided.

Conclusion

Now that you know about these poisonous plants in Missouri here is a summary of the dangers that you should always be aware of,

• Plants such as poison Hemlock can cause convulsions and paralysis.

• The deadly nightshade may disrupt organ system functioning and affect nerve function.

• Consuming rosary peas may lead to abdominal pain, diarrhea, or hypotension.

• Consumption of water hemlock will result in severe gastric upset or muscular paralysis.

• Foxgloves can cause significant disturbances to the heart’s rhythm.

For these dangers and the ones mentioned throughout this post, you should avoid planting these plants on your lawn.

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