In honor of creepiest, scariest night of the year this post will pay tribute to some of the most horrifyingly poisonous plants on the planet. Terrifying trees and plants have long played a part in the imagination of humans, from the 1800s when rumors of a man-eating tree received widespread public attention to the more recent and infamous Seymour from Little Shop of Horrors. While man-eating plants may be a stretch, many plants have evolved some toxic tactics to deter predation and successfully reproduce. Reactions to poisonous plants may vary by the person’s sensitivity, however, some plants and plant parts can be deadly, becoming acquainted with these species could save you from more than an itchy, ugly rash.
The manchineel tree, Hippomane mancinella, was called manzanita de la muerte by Spanish conquistadors due to the toxicity of almost every part of the plant. Its native range is from South Florida, through the Caribbean to Central Florida. Sap is a painful irritant to skin and eyes, inhaling the burning wood can cause internal damage, ingestion of the deceptive crabapple-like fruit causes blisters and burning in the mouth and dripping sap can take the paint off of your car. Also called the beach apple, these trees can grow to 50 feet and be found near the beach, enticing hapless tourists. The story goes that Ponce de Leon succumbed to wounds inflicted by a Calusa warrior’s arrow dipped in poison from the Manchineel tree.
Aconite, Aconitum napellus, is a perennial wildflower also referred to as monkshood due to the shape of its flower. It grows from 2 to 6 feet tall and produces blueish to whitish flowers in bunches at the top of stalks. Every part of this plant contains the toxin aconitine which is dangerous to ingest or even touch. Poisonings rarely occur but when they do it is usually due to mistaken identity, gardeners or lay botanists may mistake it for wild carrot or an edible herb. Consumption can result in burning in the mouth, vomiting, diarrhea, increased salivation, heart rate and blood pressure irregularities, coma and even death. Historically, aconite has been used in the intentional harm to people and animals; Nazi scientists coated bullets with aconitine and shepherds used arrows laced with the toxin to kill wolves.
Jimsonweed, Datura stramonium, is a less than desirable introduction into the United States, and is now distributed throughout. With brutally serrated leaves, purplish branches and twigs and unpleasant odor, this is every bit the plant of nightmares. The fruits are particularly wicked looking, developing into green, spiky, 2 inch spheres. The beautiful white or purple trumpet-shaped flower produce poisonous petals and nectar. Atropine and scopolamine are the toxins lacing every bit of this plant. Sometimes referred to as Jamestown weed, due its voluminous presence at Jamestown, settlers mistook the plant for something edible and suffered from hallucinations, delirium, arrhythmia, comas and seizures.
White snakeroot, Eupatorium rugosum, is a weed native to the U.S. and is commonly found throughout the eastern and southern regions. It can grow to 5 feet tall, has leaves with serrated edges and flowers grow in small, white clusters at the end of stalks. “Milk sickness” is the illness displayed by people who eat meat or milk from a cow which has grazed on snakeroot. This is because the plant contains tremetol, a powerful toxin. Symptoms experienced during milk sickness include; weakness, loss of appetite, pain and muscle stiffness, vomiting, abdominal pain, severe constipation, coma and, in some instances, death. People were commonly suffering from milk sickness frequently up until the 1920s until farmers realized where it was coming from and eradicated the weed from grazing properties.
The English yew, Taxus baccata, is a an evergreen tree which produces fleshy, red fruits. It can grow to 60 or 70 feet and is common throughout England. It is also cultivated and sold in the U.S. as an ornamental. Every part of this tree contains poisonous alkaloids except for the flesh of the small fruits. Ingestion of needles and seeds may cause dizziness, dry mouth, pupil dilation, weakness, arrhythmia and, in some cases, death. In spite of the poisonous qualities, these trees have long been valued for their wood in the production of bows and medicinal properties. Today, extracts from yew trees is used to make paclitaxol, a drug used in the treatment of ovarian, breast and lung cancers.
The castor bean, Ricinus communis, is widely common and used in landscaping and for castor oil production. As the scientific name may suggest it is also the plant from which the poison, Ricin, is derived. The castor bean is a fast-growing, shrubby tree commonly used in landscapes due to its hardiness and aesthetic appeal. While castor oil comes from the seeds of this plant and is harmless, and sometimes even helpful as a homeopathic remedy, ricin is present in low levels throughout the plant but concentrations are highest in the seed coatings. Accidental poisonings are rare, occurring most often in small children or pets. As few as 3 seeds, which are green with brown markings, could kill a child who swallows them. Symptoms of ricin poisoning include abdominal cramps, vomiting, internal bleeding, kidney failure and circulation problems. Many people will suffer from allergies to seed dust or pollen and will experience coughing, difficulty breathing and/or muscle weakness.
The rosarypea, Abrus precatorius, has very pretty seeds which are often used to make jewelry, and as the name suggests, rosary beads. These aggressive vines are native to Indonesia but have introduced globally. However, the seeds contain the toxin abrin which is dangerous but only when the shell is broken, any scratch or damage will make it poisonous. Abrin is more toxic than ricin, 3 micrograms is enough to be deadly, and that is less than would be contained in a single seed. In humans, abrin bonds to cell membranes preventing protein synthesis. Inhalation can cause fever, difficulty breathing and fluid in the lungs. Ingestion of a seed with the coating broken will lead to severe nausea, vomiting, dehydration, followed by organ failure and death within 3 to 4 days.
The water hemlock, Cicuta maculata, is an attractive wildflower with an upright habit, purplish, striped leaves and clusters of small white flowers. Its white roots are sometimes mistaken for a wild parsnip, this can be a fatal mistake. Cicutoxin is present throughout the plant but found in the highest concentration in the roots. Native to North America, it is thought to be the most toxic plant on the continent. This wildflower can grow to 6 feet in height and is an obligate wetland plant; usually found along stream banks, wetlands and marshy areas. Anyone unfortunate enough to mistake this plant for a parsnip will suffer violent and painful convulsions, vomiting, muscle cramps and tremors. Those who survive cicutoxin poisoning will suffer long-term health effects, such as amnesia. No amount of water hemlock is deemed safe for consumption.
Oleander, Nerium oleander, is an attractive, dense shrub, native to the far east and mediterranean but has been introduced into the U.S. where it thrives. Growing to a potential 18 feet, oleander has thick, dark-green leaves and white, yellow or pink flowers growing in clusters. It is considered one of the most poisonous plants in the world containing oleandrin and neriine and has been known to poison people who eat honey produced by bees pollinating oleander plants. Unlike many toxic plants oleander is poisonous to animals as well as humans. A single oleander leaf ingested by a child can prove fatal. Consumption usually produces symptoms such as diarrhea, vomiting, severe stomach pain, drowsiness, dizziness, arrhythmia and often, death.
In 2009, poison control centers across the United States handled 58,687 cases regarding plant poisonings. Being able to identify poisonous plants could save your life and protect your family and pets. The above does not constitute an extensive list, by any means, for help identifying possible toxic plants on your property review regional plant lists and contact your arborist for assistance.
