Plants have many uses, from medicine, to food to bringing joy, but many plants have been used by many humans as ways of bringing pain, discomfort and even death to each other. While you may have heard of some of the plants on this list, there are a few surprising entries, as well as alarming explanations of exactly what each individual plant poison does to a body.
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Who best to create the deadliest plants list than the team at The Poison Garden in Alnwick? It's a garden that is home to all of these deadly plants and more: some of the nastiest plants in the world.
Below is an extract from the book The Poison Garden, Alnwick A-Z of Poisonous plants, written by Fiona Mitcheson, which you can buy here.
Note: This extract is intended for educational purposes only and is not intended as a source of medical advice as the plants in this book can cause death or injury. Gardens Illustrated, The Alnwick Garden author, designer and publisher can accept no liability for any injuries caused by the use of plants referenced in this book.
The world's most deadliest plants
Atropa belladonna
Deadly Nightshade
This perennial herbaceous plant is found in parts of Europe, Asia, and North America. With its deep purple flowers and shiny black berries, it is a plant of captivating beauty and lethal toxicity. The name Deadly Nightshade is said to record an old superstition that at certain times the plant takes the form of an enchantress of exceeding loveliness, whom it is dangerous to look upon.
Children have died from eating just three of the sweet-tasting, shiny black berries and adults from about 12 berries.
The roots are the deadliest, followed by the stem, leaves, flowers and finally the berries. These alkaloids act as anticholinergic agents, blocking the neurotransmitter acetylcholine in both the peripheral and central nervous systems, leading to a range of physiological and psychological effects. Symptoms can include fever, dry mouth, blurred vision, hallucinations, seizures and in severe cases, death. The onset of symptoms usually occurs within an hour after ingestion. It speeds up the heart until it gives up and causes a cardiac arrest.
Castor Bean, Castor Oil Plant
Ricinus communis
The Latin name Ricinus is said to mean tick, as the seed of this plant resembles a blood-filled tick and it can be traced back to 4000BC, the seed known to have been found in Egyptian tombs and mentioned in the 'Ebers Papyrus'. Ancient Greeks used to use the oil from the seeds (known as castor oil), as an ointment to help heal wounds and to burn for light. It wasn’t until the 18th century that the laxative properties of the oil were discovered, leading to this plant being extensively grown and used.
The seeds within the pods are the most dangerous part of the plant, rich in a toxic protein called Ricin.
Ricin inhibits protein synthesis in the body which leads to cellular death and organ failure within a few days of being poisoned. It was used during the First World War to punish Fascist supporters and it was considered for use as a biological weapon in the Second World War although it was not used. In the UK Ricin falls under the Chemical Weapons Act 1996 where by it is illegal to acquire, produce, possess, or use without an appropriate licence issued by a UK National Authority.
Ricin was used in the famous umbrella murderer in 1978 when Georgi Markov was stabbed in the leg with an umbrella.
Giant Hogweed
Heracleum mantegazzianum
Giant hogweed is an invasive and harmful plant introduced to Britain in the 19th-century. Originally thought to be from the Caucasus region of Europe, it now populates around the world.
Giant hogweed contains furanocoumarins which become toxic when activated by sunlight. When the human body encounters sap from hogweed containing this toxin and is exposed to sunlight, it causes severe burns on the skin. Quite quickly this results in painful blisters, perhaps purplish or blackened scars and usually occurs immediately, or sometimes up to 48 hours after exposure. This plant is not lethal; however, these blisters remain on your skin for years and will need to be kept covered from direct sunlight to avoid future flare up.
Gympie Gympie
Dendrocnide moroides
The Gympie Gympie is an Australian native plant that has earned a fearsome reputation as a result of its painful and sometimes debilitating sting.
The key components behind the plant’s excruciating sting are the stinging hairs, stem and fruit. These hairs contain a potent neurotoxin, called moroidin, injected into the skin upon contact, similar to how hypodermic needles work. The injected hairs break off in the skin. They are made of silica, which the body cannot break down, and inject a toxin directly into the bloodstream. Moroidin affects nerve endings, leading to severe pain, localised inflammation and heightened sensitivity in the affected area. Due to the hairs not being able to break down in the body they cause the sting to stay and in some cases, the pain can last for days, weeks, or even months. Contact with the Gympie Gympie results in immediate intense pain, likened to being burned by hot acid or by electrocution and symptoms can escalate to include swelling, itching and localised sweating. In extreme cases, the excruciating pain can lead to shock and long-term nerve damage.
Monkshood
Aconitum napellus
Monkshood, a close relative of Wolfsbane, is another member of the Aconitum genus. Also known as Aconitum napellus, this plant is native to western and central Europe. Its name derives from the hood-like shape of its blue or purple flowers.
Monkshood was historically used as a 'quicker kill' method to coat arrowheads during warfare. With Monkshood being extremely close to Wolfsbane, its properties to poison are extremely similar. It causes burning of the lips and mouth, numbness of the throat, intense vomiting and diarrhoea, muscular weakness and spasms. It was used by a jealous lover in a poisoning in 2009.
Laburnum anagyroides
Laburnum
The Laburnum tree has beautiful yellow hanging flowers that appear in spring and help give it the Golden Chain Tree name. One of the most deadly trees in the UK, its fruit becomes dangling pods, attractive to children as they are very similar to pea pods.
All parts of this tree are toxic and contain cytisine, which affects nicotinic receptors leading to symptoms of nausea, vomiting, convulsions and potentially death. These symptoms usually appear within an hour of ingestion with as little as 3-4 grams (around 4 pods are fatal to a child and 10-12 for an adult) with no specific known antidote. Active charcoal was used to try and soak up the poisons before stomachs were pumped to try and prevent death from poisoning.
During the 1970s, Laburnum hysteria hit the UK. Often planted around school playgrounds, many children began to get sick. Around 3,000 hospital admissions a year were put down to Laburnum poisoning, but many of these could not be proven as the children’s stomachs were pumped before they could be tested, or symptoms began to show.
Water Hemlock
Oenanthe crocata
Water Hemlock is one of the most dangerous plants which thrives in marshes, ditches, swamps, and meadows. It has umbrella-shaped clusters of white flowers on a stem growing to around 2.1m. Similar to and often mistaken for coriander, parsnip and carrot, this root has caused a few tragedies over the years.
Water Hemlock contains a highly toxic polyacetylene compound called oenanthotoxin, which disrupts the nervous system causing severe convulsions and potentially death. Symptoms of poisoning showing within an hour of being exposed may include nausea and vomiting, leading rapidly to seizure. The toxin, once in the body, starts to constrict muscles enough to rip from bones or snap bones in all different directions. This can lead to a state of pre-death paralysis as the sufferer curls into a ball. Once life has ended, bone and muscles will remain in the constricted shape and must be broken to fit the corpse into a coffin. As happens with strychnine, the deceased displays a creepy facial smile. Oenanthe crocata has been dubbed as the UK’s most poisonous plant.
False Hellebore
Veratrum
False Hellebore, a distant relative to the Hellebore, has long stems that grow tall and produce big oval smooth leaves. Flowers appear from the middle of the stem and spread up to the top in bunches. Depending on the variety, colours tend to be white for Veratrum album and blacky-purple for Veratrum nigrum.
All parts of this plant are poisonous, and contain alkaloids such as veratridine, jervine and protoverative. These alkaloids interfere with sodium channels affecting the cardiovascular and nervous systems. Symptoms of poisoning from the False Hellebore include vomiting, diarrhoea, hypotension and bradycardia usually appearing within a few hours. The dry root of Veratrum nigrum can lower blood pressure and slow the heart rate but it is extremely difficult to prepare a safe and effective dose.
Khat
Catha edulis
Khat is a slender evergreen tree or shrub native to the Horn of Africa and the Arabian Peninsula. It is a slow-growing plant that can reach a height of 25 metres and its leaves are an oval shape. The leaves are bitter tasting and are chewed for the stimulants it gives off, which are psychoactive alkaloids, cathinone and cathine. These affect the central nervous system. Chewing these leaves can make people feel more alert and talkative, and it can also cause insomnia, heart problems and feelings of anxiety and aggression. Once leaves have been harvested, it becomes a race to get them distributed as they lose the levels of cathinone sharply after 48 hours.
Currently in the UK, Khat is a Class C drug making it illegal to own or grow. Possession of this drug can lead to two years in prison and an unlimited fine. If you are caught growing or distributing this drug, then expect up to 14 years in prison and an unlimited fine.
Henbane
Hyoscyamus niger
Henbane is a hairy, sticky plant that grows up to 75cm in height. The creamy- yellow, funnel-shaped flowers grow to 2-3cm and have dark purplish centres. It comes from the same family as Deadly Nightshade and has some similar affects.
Henbane contains propane alkaloids such as hyoscyamine and scopolamine that affect the nervous system by inhibiting acetylcholine (neurotransmitter) and leads to anticholinergic toxicity (blocking messages throughout the body). Symptoms can include a dry mouth, blurred vision, hallucinations, seizures and even death within a few hours. Scopolamine has also been known to be used as tablets or patches in the past to help relieve motion sickness symptoms.