Across the United States, nature has produced an astonishing variety of plants—some beautiful, some strange, and some deceptively deadly. While many appear harmless or even ornamental, a surprising number contain potent toxins capable of causing severe illness or death. From bright, attractive flowers to common roadside weeds, these plants can threaten humans, pets, and livestock alike. In this guide, we explore the most toxic plants in each state, highlighting their poisonous properties, symptoms of poisoning, and why they warrant respect. Even the most unassuming leaf or flower can conceal lethal power.
1. California – Oleander (Nerium oleander)
Oleander is one of the most dangerous ornamental plants commonly found across California, especially along highways and in gardens. Its attractive pink, white, or yellow flowers hide a deadly secret: every part of the plant contains toxic cardiac glycosides, particularly oleandrin. Ingestion can cause nausea, vomiting, slowed heart rate, severe arrhythmias, and sudden cardiac arrest. Even smoke from burning oleander wood can be poisonous. Historically, poisoning incidents have occurred when branches were used as cooking skewers. Despite its beauty and drought resistance, oleander remains a serious risk to humans and animals.
2. Ohio – Poison Hemlock (Conium maculatum)
Poison hemlock thrives along Ohio’s roadsides, ditches, and fields. This tall plant resembles parsley or wild carrot, which makes it especially dangerous. It contains several potent alkaloids, including coniine, a neurotoxin that causes muscle paralysis and respiratory failure. Poison hemlock is infamous for its historical use in executions, including the death of Socrates. Ingesting even small amounts can be fatal within hours. The plant’s white umbrella-shaped flowers bloom in summer, increasing accidental exposure risks for foragers and children who mistake it for harmless wild plants.
3. Florida – Manchineel Tree (Hippomane mancinella)
Often considered the most dangerous tree in North America, the manchineel grows along Florida’s coastal areas. Its small green fruits resemble apples and are extremely toxic. The sap causes severe skin burns, while inhaling smoke from burning wood can damage the eyes and lungs. Even standing beneath the tree during rain can cause blistering, as toxins leach from its leaves. The flowers are small and unassuming, offering no warning. Historically used for poison-tipped arrows, the manchineel remains a lethal presence disguised as a tropical beach tree.
4. Texas – Jimson Weed (Datura stramonium)
Jimson weed grows aggressively across Texas fields and roadsides. Its trumpet-shaped white or purple flowers are striking, but the plant contains dangerous tropane alkaloids like scopolamine and atropine. Ingestion can cause hallucinations, extreme confusion, rapid heartbeat, seizures, coma, and death. Sometimes called “devil’s trumpet,” it has a long history tied to poisonings and misuse for its hallucinogenic effects. All parts of the plant are toxic, including seeds and flowers. Livestock poisoning is also common, making jimson weed a serious agricultural and public health concern.
5. New York – Deadly Nightshade (Atropa belladonna)
Deadly nightshade can be found in wooded areas of New York. Its glossy black berries look appealing, especially to children, but are highly poisonous. The plant contains atropine and scopolamine, which interfere with the nervous system. Symptoms include dilated pupils, dry mouth, hallucinations, seizures, and respiratory failure. Bell-shaped purple flowers bloom quietly before producing lethal fruit. Historically used in cosmetics and poisons, belladonna’s beauty masks its danger. Even a few berries can be fatal, making it one of the most treacherous wild plants in the region.
6. Arizona – Castor Bean Plant (Ricinus communis)
Common in warm Arizona climates, the castor bean plant is visually dramatic with large leaves and spiky seed pods. Its seeds contain ricin, one of the most toxic substances known. Ingesting chewed seeds can cause organ failure and death within days. The flowers are small and easily overlooked, offering no warning. Although castor oil itself is safe once processed, raw seeds are lethal. Because the plant is sometimes grown ornamentally, accidental poisonings remain a concern, especially for children and pets attracted to its unusual appearance
7. Washington – Western Water Hemlock (Cicuta douglasii)
Western water hemlock is considered the most poisonous plant in North America and is found in wetlands across Washington State. Its white flower clusters resemble Queen Anne’s lace, making misidentification common. The roots contain cicutoxin, a fast-acting neurotoxin that causes violent seizures, respiratory failure, and death. Symptoms can appear within minutes of ingestion. Even small amounts are lethal. Historically responsible for numerous accidental deaths, this plant’s presence near streams and ponds makes it especially dangerous to hikers and children exploring natural areas.
8. Georgia – Yellow Jessamine (Gelsemium sempervirens)
Yellow jessamine is Georgia’s state flower, yet it is highly toxic. Its fragrant yellow blossoms contain gelsemine, a powerful alkaloid that affects the nervous system. Ingestion can cause dizziness, slowed breathing, paralysis, and death. Even honey made from its nectar can be poisonous. Despite its pleasant scent and attractive flowers, the plant poses serious risks when consumed. Livestock poisonings have been recorded, and human cases often result from mistaken herbal use. Yellow jessamine is a striking example of beauty masking danger in plain sight.
9. Colorado – Monkshood (Aconitum napellus)
Monkshood grows in Colorado’s mountainous regions and is easily recognized by its deep blue, hood-shaped flowers. It contains aconitine, a deadly neurotoxin that can be absorbed through the skin. Ingestion or improper handling can cause numbness, irregular heartbeat, respiratory failure, and death. Historically used in poisoned arrows, monkshood is one of the most toxic flowering plants in the world. Even touching the plant without gloves can be dangerous. Its elegant appearance contrasts sharply with its lethal chemistry.
10. North Carolina – Yew (Taxus species)
Yew trees are commonly planted in North Carolina landscapes. While their red berries appear harmless, nearly all parts of the plant contain taxine alkaloids that disrupt heart function. Ingesting leaves or seeds can lead to sudden cardiac arrest without warning symptoms. The flowers are subtle and easily ignored. Yew poisoning is often fatal because the onset is rapid and unpredictable. Livestock and pets are especially vulnerable. Despite its use in medicine and landscaping, the yew remains one of the most dangerous plants growing in residential areas.
11. Michigan – White Snakeroot (Ageratina altissima)
White snakeroot grows in wooded and shaded areas throughout Michigan. It produces small clusters of white flowers that appear harmless, yet the plant contains tremetol, a potent toxin. When ingested, it can cause nausea, muscle weakness, tremors, and heart failure. Historically, white snakeroot was responsible for “milk sickness” in the 19th century, when toxins passed from cows that ate the plant into milk consumed by humans, causing widespread deaths. All parts of the plant are poisonous, especially the leaves and stems. Its subtle appearance makes it particularly dangerous to livestock and unsuspecting foragers.
12. Pennsylvania – Mountain Laurel (Kalmia latifolia)
Mountain laurel, Pennsylvania’s state flower, is stunning when in bloom with its pink and white blossoms. Despite its beauty, every part of the plant is toxic due to grayanotoxins. Ingestion can lead to drooling, vomiting, slowed heart rate, seizures, and respiratory failure. Even honey made from mountain laurel nectar can be poisonous. Native to forests and hillsides, the plant is often used ornamentally, increasing accidental exposure. Its thick evergreen leaves remain toxic year-round, making mountain laurel a hidden but persistent danger in the state.
13. Louisiana – Water Hemlock (Cicuta maculata)
Water hemlock thrives in Louisiana’s swamps and wetland areas and is one of the most lethal plants in North America. It features clusters of small white flowers and hollow stems that resemble edible plants. The roots contain cicutoxin, which causes rapid-onset seizures, violent convulsions, and death, sometimes within an hour. Even minimal exposure can be fatal. Historically, water hemlock has caused numerous accidental poisonings. Its presence near water sources makes it especially dangerous for children and animals exploring muddy or flooded environments.
14. Oregon – Foxglove (Digitalis purpurea)
Foxglove is widespread in Oregon and admired for its tall spikes of purple, pink, or white bell-shaped flowers. Beneath its ornamental charm lies a powerful toxin: cardiac glycosides that interfere with heart rhythm. Ingesting foxglove can cause nausea, confusion, irregular heartbeat, and fatal cardiac arrest. Although compounds from the plant are used medicinally in controlled doses, consuming any part of the raw plant is extremely dangerous. Foxglove often grows along trails and forest edges, increasing the risk of accidental exposure for hikers and pets.
15. New Mexico – Desert Rose (Adenium obesum)
Though more common as an ornamental plant, desert rose can be found in gardens across New Mexico. Its thick stem and bright pink flowers attract attention, but the plant contains toxic cardiac glycosides similar to oleander. Ingestion can lead to vomiting, slowed heartbeat, dizziness, and death. Traditionally, the sap was used on poison arrows. Even handling broken stems can irritate skin. The contrast between its vibrant flowers and lethal chemistry makes the desert rose especially deceptive in arid environments.
16. Virginia – Pokeweed (Phytolacca americana)
Pokeweed is common throughout Virginia and easily recognized by its tall stalks, white flowers, and dark purple berries. While some parts are mistakenly consumed when improperly prepared, the plant is highly toxic. The roots and berries contain phytolaccatoxin, which can cause severe gastrointestinal distress, respiratory issues, and seizures. Children are often drawn to the berries, increasing poisoning risk. Despite its frequent appearance in fields and backyards, pokeweed remains one of the most dangerous native plants in the region.
17. Nevada – Death Camas (Zigadenus species)
Death camas grows in Nevada’s deserts and grasslands and is often mistaken for edible wild onions due to its similar shape. Unlike onions, death camas has no onion smell and produces clusters of white or cream-colored flowers. The plant contains toxic alkaloids that affect the nervous system, causing nausea, low blood pressure, seizures, and respiratory failure. Death can occur without prompt medical treatment. Misidentification during foraging has caused numerous poisonings, making this plant particularly hazardous in rural areas.
18. South Carolina – Carolina Jessamine (Gelsemium sempervirens)
Carolina jessamine produces bright yellow, trumpet-shaped flowers that bloom early in spring. Despite its pleasant fragrance, the plant contains gelsemine, a powerful neurotoxin. Ingestion can cause dizziness, paralysis, slowed breathing, and death. Even honey made from its nectar can be toxic. The plant climbs fences and trees, often growing near homes and roadsides. Its popularity as an ornamental vine increases the risk of accidental exposure, especially for pets and children.
19. Minnesota – Wild Parsnip (Pastinaca sativa)
Wild parsnip grows widely in Minnesota fields and roadsides and produces clusters of small yellow flowers. The sap contains toxic chemicals that cause severe skin burns when exposed to sunlight, a condition known as phytophotodermatitis. Ingestion can also cause stomach pain and neurological symptoms. Skin contact followed by sun exposure can result in blistering and long-term scarring. Because it resembles harmless plants like Queen Anne’s lace, wild parsnip is frequently encountered and underestimated.
20. Alabama – Rosary Pea (Abrus precatorius)
Rosary pea is occasionally found in Alabama and is easily recognized by its bright red seeds with black markings. These seeds contain abrin, a toxin even more potent than ricin. Chewing or damaging a single seed can be fatal. Historically used in jewelry and ornaments, the seeds pose a hidden risk if broken. Symptoms include vomiting, organ failure, and death. Despite its small size, rosary pea is among the most dangerous plants in the world.
21. Kentucky – Mountain Death Camas (Zigadenus glaberrimus)
Mountain death camas grows in Kentucky’s meadows and open woodlands. Its creamy-white flowers may appear delicate, but the entire plant is packed with alkaloids that attack the nervous system. Ingestion leads to nausea, vomiting, dizziness, slowed heartbeat, convulsions, and often death if untreated. The bulbs closely resemble edible wild onions, increasing accidental poisonings. Livestock, children, and foragers are all at risk. The plant’s subtle beauty conceals its lethal potential, making it a silent hazard in fields and along rural trails throughout the state.
22. Illinois – Dumbcane (Dieffenbachia spp.)
Dumbcane is a popular ornamental plant in Illinois homes and offices, recognized for its large variegated leaves. Its leaves and stems contain calcium oxalate crystals that can cause immediate oral pain, swelling, and difficulty swallowing if ingested. In severe cases, breathing can be impaired. While not usually fatal, small children or pets can experience dangerous reactions. Even touching the plant and transferring sap to the mouth or eyes can cause irritation. The plant’s aesthetic appeal masks the serious risk it poses in everyday household environments.
23. Missouri – Foxglove (Digitalis purpurea)
Foxglove is commonly found in Missouri gardens and wild areas. Its tall spikes of tubular purple or white flowers contain digitalis glycosides, which are extremely toxic. Ingestion can cause nausea, vomiting, slow or irregular heartbeat, seizures, and fatal heart arrhythmias. Even handling the plant carelessly can transfer toxins to the skin. Historically, foxglove extracts were used medicinally under strict supervision, but raw consumption is highly dangerous. The plant’s ornamental value belies its deadly potential, posing a serious risk to curious children, pets, and unknowing foragers.
24. Wisconsin – Water Hemlock (Cicuta maculata)
Water hemlock, the deadliest plant in Wisconsin, grows in wet meadows, marshes, and stream banks. Its clusters of small white flowers make it look deceptively like harmless wildflowers. The roots and stems contain cicutoxin, a potent neurotoxin that triggers violent seizures, respiratory failure, and death. Even minimal ingestion can be fatal within hours. The plant’s prevalence near water sources increases the risk for hikers, children, and livestock. Careful identification is critical, as misidentifying it for edible plants has historically resulted in fatal poisonings.
25. Tennessee – Foxglove (Digitalis lanata)
Tennessee’s foxglove is a striking plant with bell-shaped flowers in shades of purple and white. Its leaves and flowers contain cardiac glycosides, making any ingestion potentially lethal. Symptoms include nausea, confusion, irregular heartbeat, and sudden cardiac arrest. While the plant is often cultivated for its beauty, its natural toxicity has caused accidental poisonings among children, pets, and even experienced gardeners. Handling it without care can transfer toxins to the skin, reinforcing its reputation as a deceptively beautiful but deadly flowering plant.
26. Massachusetts – Monkshood (Aconitum napellus)
Monkshood grows in cool, shaded areas of Massachusetts and is recognized by its hood-shaped deep blue flowers. Containing aconitine, the plant is deadly if ingested or improperly handled. Symptoms include numbness, dizziness, slowed heartbeat, convulsions, and death. Its elegant flowers have long masked its danger, historically being used in poisonings and as an arrow toxin. Even touching the plant without gloves can transfer enough toxin to cause serious health problems. Monkshood’s beauty contrasts sharply with its lethal potential, making it one of the most dangerous plants in the state.
27. North Dakota – Poison Hemlock (Conium maculatum)
Poison hemlock spreads along roadsides, ditches, and riverbanks in North Dakota. Its white umbrella-shaped flowers bloom in summer, attracting accidental contact. The plant contains coniine and other alkaloids that interfere with the nervous system, causing muscle paralysis, respiratory failure, and death. Misidentification with harmless wild carrot or parsley increases the risk. Livestock and children are especially vulnerable. Historical records show poison hemlock’s lethal effects dating back to ancient Greece. Despite its unassuming appearance, it remains one of the most toxic plants in the state.
28. Indiana – Water Hemlock (Cicuta douglasii)
Indiana’s water hemlock is notorious for its extreme toxicity. Found in wetlands, streams, and damp meadows, it produces small clusters of white flowers that can be easily mistaken for edible plants. The plant’s roots contain cicutoxin, a fast-acting neurotoxin that induces violent seizures, respiratory failure, and death. Even minor exposure can be fatal. It poses a significant risk to children, hikers, and livestock. Water hemlock is a prime example of a plant that looks harmless but carries one of the most dangerous toxic profiles in the region.
29. Mississippi – Rosary Pea (Abrus precatorius)
Rosary pea grows sporadically in Mississippi and is known for its striking red seeds with black markings. The seeds contain abrin, one of the most potent plant toxins in the world. Even a single chewed seed can cause vomiting, organ failure, and death. Historically, seeds were used in jewelry, leading to accidental poisonings. While the vine itself is attractive with small flowers, its deadly seeds pose hidden dangers to children, pets, and unsuspecting adults. Extreme caution is required when handling or encountering this plant in the wild or gardens.
30. Arkansas – Poison Ivy (Toxicodendron radicans)
Poison ivy grows abundantly in Arkansas forests, fields, and suburban areas. Its green leaves turn red in fall, and clusters of white berries may attract children. While rarely fatal, the plant’s urushiol oil causes severe skin rashes, blistering, swelling, and, in rare cases, systemic reactions. Direct contact can spread the toxin to others, making it highly contagious. Although not deadly like some other plants, poison ivy’s ability to cause extreme irritation and secondary infections makes it one of the state’s most notorious plants for humans and pets alike.
31. Hawaii – Cerbera odollam (Suicide Tree)
Hawaii’s warm, coastal environments support the rare but deadly Cerbera odollam, known as the “suicide tree.” Its cream-colored flowers and mango-like fruit are deceptively beautiful. Every part contains cerberin, a potent cardiac toxin that can induce nausea, irregular heartbeat, seizures, and death. Historically, it has been used for untraceable poisonings in Southeast Asia. Even minimal exposure, such as handling leaves or consuming the fruit, can be fatal. Its presence in ornamental plantings and coastal areas makes it a hidden danger, reminding visitors that nature’s beauty can sometimes mask lethal threats.
32. Alaska – Monkshood (Aconitum spp.)
Monkshood thrives in Alaska’s alpine meadows and forested areas, identifiable by its hood-shaped violet-blue flowers. The plant contains aconitine, a neurotoxin that can paralyze the heart and respiratory system. Symptoms include numbness, vomiting, slow heartbeat, and potentially death. Even touching it without gloves can transfer enough toxin to cause serious reactions. Historically used on poisoned arrows, monkshood is deceptively dangerous, hiding lethal properties beneath its elegant blooms. Hikers and foragers must exercise extreme caution, as misidentification with harmless wildflowers is common in the region.
33. Connecticut – Lily of the Valley (Convallaria majalis)
Lily of the valley is widely cultivated in Connecticut gardens for its fragrant, bell-shaped white flowers. However, all parts of the plant contain cardiac glycosides that can cause nausea, vomiting, slowed heart rate, seizures, and death. Its sweet scent and delicate appearance make it particularly deceptive. Even small amounts can be dangerous to children and pets. Despite its use in traditional medicine in carefully controlled doses, accidental ingestion remains a serious risk. Awareness is critical when planting or encountering this ornamental species.
34. Maine – Foxglove (Digitalis purpurea)
Foxglove grows in Maine’s forests and garden landscapes. Its tubular flowers in shades of pink, purple, and white contain potent cardiac glycosides. Ingesting the leaves or flowers can cause nausea, irregular heartbeat, confusion, seizures, and death. Even handling the plant carelessly can transfer toxins to the skin. Historically used for heart medicine under strict supervision, foxglove remains highly toxic if consumed raw. Its attractive flowers lure attention, hiding one of the deadliest plants commonly found in northern gardens and wild areas.
35. Vermont – Water Hemlock (Cicuta maculata)
Water hemlock thrives in Vermont’s marshes, stream banks, and wet meadows. Its small, white clustered flowers and hollow stems resemble edible plants, increasing accidental poisonings. The roots contain cicutoxin, a fast-acting neurotoxin that causes seizures, respiratory failure, and death. Even small amounts can be lethal. Historically responsible for numerous fatalities, water hemlock remains a serious hazard to children, hikers, and livestock. Its subtle, unassuming appearance makes it particularly treacherous, despite being one of the most toxic plants in North America.
36. West Virginia – Poison Hemlock (Conium maculatum)
Poison hemlock grows widely along West Virginia’s roadsides and riverbanks. Its umbrella-shaped white flowers bloom in summer and can easily be mistaken for parsley or wild carrot. The plant contains coniine and other alkaloids that paralyze the nervous system, causing muscle weakness, respiratory failure, and death. Livestock and children are especially vulnerable. Historical use as a poison, including the execution of Socrates, illustrates its lethality. Despite its unassuming appearance, poison hemlock is a hidden but deadly presence in fields and wetlands throughout the state.
37. New Jersey – Rosary Pea (Abrus precatorius)
Rosary pea is a vine occasionally seen in New Jersey gardens. Its bright red seeds with black markings contain abrin, an extremely potent toxin. Chewing a single seed can lead to vomiting, organ failure, and death. The small flowers are unassuming, hiding the seeds’ danger. Historically used for jewelry, accidental poisonings still occur if seeds are broken or handled improperly. The plant’s vibrant appearance disguises its lethal properties, making it one of the most dangerous ornamental plants encountered in the state.
38. Rhode Island – Yellow Jessamine (Gelsemium sempervirens)
Yellow jessamine, Rhode Island’s state flower, produces fragrant yellow trumpet-shaped blooms that appear harmless. Yet all parts contain gelsemine, a neurotoxin that can cause dizziness, paralysis, slowed breathing, and death if ingested. Even honey made from its nectar is toxic. The plant climbs fences and trees, often growing near homes and public areas, increasing accidental exposure risk. Its ornamental appeal hides a serious danger for children, pets, and foragers who may mistake it for a safe flowering vine.
39. New Hampshire – Foxglove (Digitalis purpurea)
Foxglove in New Hampshire is appreciated for its tall spikes of pink, purple, or white bell-shaped flowers. Beneath their beauty lies a potent cardiac toxin. Ingestion can lead to nausea, vomiting, irregular heartbeat, seizures, and death. Even skin contact can transfer toxins. Historically used as a heart medicine in controlled doses, the raw plant remains extremely hazardous. Its prevalence along trails, gardens, and shaded areas increases accidental exposure risk. Foxglove exemplifies a plant whose ornamental beauty masks a serious threat to humans and animals alike.
40. Delaware – Oleander (Nerium oleander)
Oleander thrives in Delaware’s warm, suburban areas and roadside plantings. Its attractive pink, white, or yellow flowers conceal highly toxic cardiac glycosides. Ingestion can cause nausea, vomiting, slowed heartbeat, arrhythmias, and sudden death. Even inhaling smoke from burning oleander can be harmful. Historically, accidental poisonings occurred when branches were used as cooking skewers. Its ornamental value and drought tolerance make it popular, but it remains one of the most lethal plants in the state, posing a risk to children, pets, and unsuspecting gardeners.
41. Wyoming – Death Camas (Zigadenus elegans)
Death camas grows in Wyoming’s grasslands and open meadows. Its clusters of white flowers and bulb-like roots closely resemble edible wild onions. Containing toxic alkaloids, death camas ingestion leads to nausea, low blood pressure, convulsions, respiratory failure, and death. Livestock and humans are at risk, as misidentification is common during foraging. Despite its delicate flowers, the plant is one of the deadliest in the state. Knowledge and caution are crucial for anyone exploring natural areas where death camas thrives.
42. Montana – Western Water Hemlock (Cicuta douglasii)
Western water hemlock grows abundantly in Montana’s wetlands, streams, and riverbanks. Small clusters of white flowers disguise its extreme toxicity. The roots contain cicutoxin, which induces violent seizures, respiratory failure, and rapid death. Even minor ingestion can be fatal. Historical cases of accidental poisoning underline its lethality. Its presence near accessible water sources makes it dangerous to children, hikers, and livestock. The plant’s innocuous appearance masks one of the deadliest natural toxins in the region.
43. Iowa – Pokeweed (Phytolacca americana)
Pokeweed is widespread in Iowa fields and wooded areas, producing tall stalks, white flowers, and dark purple berries. Its roots and berries contain phytolaccatoxin, which causes nausea, vomiting, respiratory issues, seizures, and potentially death. Children are particularly drawn to the berries, increasing accidental exposure. Pokeweed’s vibrant flowers and berries hide serious toxicity, making it one of the most dangerous plants in the state. Proper identification and caution are essential for anyone encountering this native species.
44. South Dakota – White Snakeroot (Ageratina altissima)
White snakeroot is found throughout South Dakota’s wooded areas and fields. Its clusters of small white flowers conceal tremetol, a toxin that historically caused “milk sickness” when ingested indirectly through cow’s milk. Symptoms include nausea, muscle weakness, tremors, and heart failure. The plant’s leaves and stems are especially dangerous, and livestock grazing can result in fatal poisoning. Foragers, hikers, and children must be cautious, as white snakeroot appears deceptively harmless in the wild despite its lethal potential.
45. Kansas – Poison Ivy (Toxicodendron radicans)
Poison ivy grows widely across Kansas forests, fields, and suburban areas. Its green leaves turn red in fall, and clusters of white berries attract attention. Contact with urushiol oil causes severe skin rashes, blistering, and, in rare cases, systemic reactions. While rarely fatal, infections from scratching can be serious. The plant spreads easily and can transfer oil to others, making it highly contagious. Despite being non-lethal compared to some other plants, poison ivy remains one of the most notorious and irritating plants in the state.
46. Oklahoma – Water Hemlock (Cicuta maculata)
Water hemlock thrives in Oklahoma’s wetlands, streams, and damp fields. Its white flower clusters make it deceptively similar to edible plants, but its roots contain cicutoxin, a neurotoxin that causes violent seizures, respiratory failure, and death. Even minor ingestion is fatal. Livestock and children are particularly vulnerable. Historical poisonings highlight its lethality. Water hemlock’s subtle appearance and widespread growth make it one of Oklahoma’s deadliest plants, requiring extreme caution when encountered in the wild.
47. Montana – Yellow Jessamine (Gelsemium sempervirens)
Yellow jessamine grows along Montana’s gardens, fences, and roadsides. Its bright yellow trumpet-shaped flowers contain gelsemine, a neurotoxin that can cause dizziness, paralysis, slowed breathing, and death. Even honey made from the nectar can be toxic. The plant climbs structures and trees, making accidental exposure more likely. Its attractive flowers disguise its lethality, especially for children, pets, and unsuspecting foragers. Yellow jessamine demonstrates how ornamental plants can pose hidden threats in both cultivated and wild areas.
48. Nevada – Death Camas (Zigadenus venenosus)
Death camas grows in Nevada’s grasslands and arid regions. Clusters of small white flowers and bulb-like roots resemble wild onions. Containing alkaloids, ingestion leads to nausea, low blood pressure, convulsions, respiratory failure, and death. Misidentification is common, putting livestock and humans at risk. Despite its delicate appearance, death camas is one of the deadliest plants in Nevada. Awareness and education are vital for anyone exploring natural landscapes where it thrives.
49. Utah – Monkshood (Aconitum spp.)
Monkshood thrives in Utah’s alpine and forested regions. Its hood-shaped purple-blue flowers contain aconitine, a neurotoxin that can paralyze the heart and lungs. Symptoms include numbness, dizziness, slow heartbeat, seizures, and potentially fatal respiratory failure. Even touching the plant without gloves can cause serious reactions. Historically used in poisoned arrows, monkshood’s elegant flowers conceal its deadly potential. Foragers, hikers, and gardeners must be vigilant to avoid accidental exposure.
50. Maine – Oleander (Nerium oleander)
Oleander, occasionally cultivated in Maine’s warm microclimates, is highly toxic despite its ornamental appeal. Pink, white, or yellow flowers conceal cardiac glycosides that can cause nausea, vomiting, irregular heartbeat, arrhythmias, and sudden death. Inhalation of smoke from burning wood can also be harmful. Historical poisonings occurred when branches were used in cooking. Even though rare in Maine, the plant remains a serious risk in gardens and public spaces, demonstrating that beauty can be deceiving when it comes to toxic flora.
