10 Poisonous Plants Found in the United States

When out in nature, beware of crossing paths with these plants.

To many, plants are dormant and harmless, they just wait to be cut down or die naturally. However, some plants harbor the most toxic and deadly poisons known to man. It is alleged that the poison hemlock killed Socrates, and there have been several incidents where children have infested the deadly nightshade. The US has more than 500 species of poisonous plants with the ability to cause harm to human beings. These are some of the plants.

10. Garden spurge

Euphorbia lathyris close-up.

The garden spurge (Euphorbia lathyris) is a smooth herb with a stiff stem and four-ranked leaves. It grows to between 2 to 3 feet, and its flowers are small and greenish-yellow. It has a three-sided fruit. The garden spurge is common in California, North Carolina, New Jersey and Texas. The milky juice has a pungent smell while its fruit is highly poisonous. It is a dangerous household remedy that mostly affects women and children because they are more likely to come into contact with the plant. The milky juice causes redness, itching, pimples, can last for weeks while the ingestion of seeds causes inflammation of the mouth and stomach, vomiting, and diarrhea. If taken in large quantities it can cause unconsciousness, nervous disorders and eventually death.

9. Poison Oak

Poison oak in the woods.

The Poison Oak (Toxicodendron diversilobum) is a woody vine or shrub that thrives in the woodlands, conifer and mixed broadleaf forests of the western United States. Its leaves and stems produce an oily substance that is itchy to the human skin and causes rashes. No part of the oak is edible meaning it cannot be ingested. Colorless bumps result in severe itching while inhaling the smoke from burning oak leads to severe respiratory complications.

8. Daffodil

Narcissus poeticus.

The daffodil (Narcissus poeticus) is a bulb plant with long, flat and dark green leaves. Its flowers are either white, yellow or orange, and has a trumpet like a cap. Although every part of the plant contains the toxic agent lycorine, it is concentrated within the bulb. The flowers contain low levels of the poison, but it comes into contact with children who are attracted by the bright colors. The poison is not very lethal to man but will result in vomiting, nausea, and diarrhea. In animals who are more likely to consume the plant in high doses, some of the effects include low blood pressure and liver damage.

7. Rose campion

Rose campion, Agrostemma githago.

The Rose Campion (Agrostemma githago) is a whitish plant with an erect stem and violet-red flowers. It has black and irregularly rounded seeds. The plant in common in grain fields of North Dakota, eastern Kansas, Florida, and Louisiana. Its poison is soluble in water and produces a sharp, burning odor. When inhaled, it leads to violent sneezing. When mixed with water the poison produces a froth that resembles soapy water. Ingestion of the poison leads to irritation of the digestive tract, vomiting, acute headache, and sharp spinal pain.

6. Water hemlock

Water hemlock, Cicuta maculata.

The water Hemlock (Cicuta maculata) is a smooth perennial plant that can grow to eight feet. It has an erect stem, several branches, dissected leaves and white flowers. It is mostly found in dump areas particularly swamps. It has a potent poison that can kill man and animals within a short time. Its roots are very poisonous but also aromatic suggesting the presence of sweet cicely, artichokes or horse-radish. Children are at high risk of ingesting the poison due to the tempting appearance of the plant. Animals ingest the plant by drinking water poisoned by the tubers or by consuming tubers stumbled upon. Victims of the poison suffer from vomiting, unconsciousness, colicky pains and convulsions that may lead to death.

5. Oleander

Nerium oleander.

The Oleander (Nerium oleander) is a beautiful flowering shrub that is common in nearly every state in the US because it is cultivated due to its attractive appearance. It is commonly found in school yards, and its victims are mostly children. The stem and leaves of the plant produce a poisonous sap that consists of cardiac glycosides, oleondroside, and saponins. These poisons are present in the plant even after it dries up. Symptoms of oleander poisoning include excess salivation, diarrhea, seizures, coma, and eventually death.

4. Poke berry

Phytolacca decandra.

The Poke berry (Phytolacca decandra) is a smooth, succulent plant that can grow to eight feet. It has a purplish stem, thick, half-woody root, and small greenish-white flowers and purple-black berries. It grows in Maine, Florida, Northern Illinois, Eastern Kansas and Texas. It is a common plant that is useful to man when deprived of its poison; the alcoholic extract from its fruit is used to cure certain skin diseases. The berries are poisonous to man but not to birds, the seeds are violently poisonous, and affect the nervous system, severe purging and can cause death by paralysis of the respiratory organs.

3. Cranberry Tree

#3 Cranberry Tree

The Cranberry Tree (Vaccinium microcarpum) is an evergreen shrub that grows in the northern United States. It grows to 7 ft. with slender, wiry stems and small green leaves. It can withstand harsh weather condition and soil pH. Its fruit is light green but turns red when ripe. The berries have been tested for several adverse effects, but there is no sufficient evidence to suggest they are harmful to humans. They are harvested for human consumption and are a good source of vitamin C. However, the presence of warfarin and anticoagulant leads to excessive bleeding. Too much consumption leads to nausea and stomach inflammation,

2. Poison Ivy

Rhus radicans.

The poison oak (Rhus radicans) can either climb or trail another plant. It has variable three-foliate leaves and greenish flowers that appear in May and June.it has a white smooth and waxy fruit that falls during winter. It grows almost everywhere, from open brush, roadsides, and even to cultivated land. The poison oak’s poison is found in a non-volatile oil that is secreted in every part of the plant even after the plant has dried up. The oil is insoluble and cannot be washed away, but a solution alcohol and lead acetate is effective against the oil. Burning of the poisonous oak releases smoke that is poisonous to humans and animals.

1. White hellebore

#1 White hellebore

The white hellebore (Veratrum album) is a stout herb that grows to about 7 feet. It has stemless leaves, fleshy root, and yellowish-green flowers. It grows wet meadows along mountain streams and in cold climates, particularly in Maine and Alaska. Its roots are poisonous to men and animals; it paralyzes the nervous system in humans. The seeds contain veratridine and cevadine which are considered toxins. Symptoms of poisons include paralysis, vomiting, loss of sight, and cathartic effects that can lead to death.

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