As is the Poison Garden, which houses more than 100 toxic plants, including the most poisonous in the world.
“These plants can kill,” says the sign attached to the black iron gate. To reinforce the warning, there is also a skull and crossbones. The warning is no joke: the enclosure behind those gates is the most lethal garden in the world. And it is open to the public.
It is in the far north-east of England, in the grounds of Alnwick Castle, ancestral home of the Dukes of Northumberland. When you see it, it may seem familiar to you: the castle served as the setting for Hogwarts, the School of Witchcraft and Wizardry, in the first two Harry Potter films — something curiously appropriate, since this garden refers to land where, centuries ago, plants used by doctors, herbalists or religious people who were often seen as wizards, wizards… or evil witches grew.
This ambiguity is not just historical or cultural: it is in the very nature of these plants. One of the things you learn in the Poison Garden is that sometimes the line between death and healing is thin.
Among the more than 100 species of toxic, intoxicating and narcotic plants it houses is, for example, what Guinness World Records considers the most poisonous plant in the world: the Common tickbetter known as castor or castor bean.
Ricinus communis, the most poisonous plant in the world.
Originally from Africa, but widely naturalized in tropical and subtropical America, it produces ricinan extremely dangerous toxin. Even so, its seeds have been used since ancient times to produce castor oila substance that, after being properly processed, does not contain ricin.
This oil has traditionally been used as a laxative and also in industrial and cosmetic applications, from lubricants to components of some skin and hair products. But, as dangerous as it is, the castor bean plant, by itself, usually causes only mild irritation upon contact — unlike other plants in this peculiar garden, capable of causing damage even just by touch or, in certain cases, by inhalation.
“Before entering, visitors need to attend a safety information session,” explained Dean Smith, garden guide, to the BBC.
They are warned not to touch, taste or smell anything. What you can do, however, is listen — and be surprised.
In your garden
Something that draws attention, especially among gardening enthusiasts, is that many of the plants that grow in the garden are very common.
“Many of the ones here grow spontaneously, and most are surprisingly easy to grow,” says Smith.
One of them is the Nerium oleanderoriginally from the Mediterranean and Sahara region, but widespread in Latin America, where it goes by various names, such as oleander, oleander, rose laurel, Saint Joseph’s rose and Roman laurel.
It is one of those beautiful but poisonous plants, as it contains cardiac glycosides that interfere with the functioning of the heart, causing everything from nausea and vomiting to potentially fatal arrhythmias.
Fortunately, its taste is so bitter that cases of poisoning are relatively rare. Still, it brings together the ideal ingredients to inspire — as has happened more than once — detective fiction stories: in addition to being a common ornamental plant, its toxicity is well known.
In this ambiguous terrain between the everyday and the lethal, the oleander easily fits into narratives as a domestic poison of silent death: a victim who apparently died of natural causes, until the autopsy and toxicological tests reveal otherwise.
But, returning to reality, it is important not to forget that the entire plant is toxic — and that its danger does not disappear when it dries: even the smoke from its wood can be harmful.
Another example of popular and toxic shrubs are rhododendrons, a genus that includes azaleas.
If they grow too close together, they poison the soil, preventing plants other than the rhododendrons themselves from growing, Smith explained.
Its leaves contain grayanotoxinawhich attacks the nervous system: “although it is unlikely that anyone will eat them, because they have a horrible taste”, he added.
However, the powerful neurotoxin is also present in the flowers. If bees collect nectar exclusively from rhododendrons, the honey acquires a dark, reddish color. Known as “crazy honey”can cause dramatic effects when ingested, as recorded by the Greek warrior and writer Xenophon, in 401 BC, in his work Anabasis:
“The soldiers who ate the honey lost their minds, suffered vomiting and diarrhea, and none were able to stand; those who ate a little seemed extremely drunk, and those who ate a lot looked crazy or even dying. They scattered in great numbers, as if the army had been defeated… but the next day, no one had died.”
They were lucky. In high doses, “mad honey” can be fatal. Two years later, in this same world of Ancient Greece, another poisonous substance would be marked like few others in cultural memory.
The classics
A hemlock It is not just in the Poison Garden, but in countless parts of the world — including much of Latin America, where it grows in abundance.
What makes it even more dangerous is its harmless appearance: an herb with small, seemingly innocent white flowers that can be confused with edible plants in the same family, such as parsley, wild carrot or fennel.
Despite not being exotic at all, hemlock is perhaps the most famous among the “classic” plants that left a mark not only for their toxicity, but also for their role in history, medicine and culture. But there are other legendary species that appear in myths, historical crimes, literature or ancient medicine.
O Aconite turnip — aconite or wolfkiller —, for example, is linked to the underworld in Greek mythology: according to some versions of the myth of Hercules and Cerberus, the plant would have sprouted from the saliva of the hellish dog.
Known as “the plant of assassins” in medieval Europe, it was used to poison arrows and weapon tips.
Contains aconitinaone of the most toxic plant alkaloids known, capable of causing fatal arrhythmias even in very small doses.
If aconite belongs to the universe of weapons and assassins, belladonna seems to have come from another imaginary: that of witches, ointments and spells whispered at midnight.
A Atropa belladonna carries centuries of European superstition. In the Middle Ages, it was associated with witchcraft and hallucinogenic potions; During the Renaissance, some women used extracts from the plant to dilate their pupils and make their eyes more seductive — the likely origin of their name: “bella donna”, or “beautiful woman”.
But behind this almost romantic aesthetic lies one of the most dangerous plants in Europe. Contains atropine e scopolaminesubstances capable of causing delirium, hallucinations, tachycardia and, in high doses, death.
And, as with several plants in the Garden of Poisons, what can kill can also cure: atropine is extracted from belladonna, still used today in ophthalmology, anesthesia and cardiac emergencies.
Between life and death
The list of poisonous plants that also cure is long.
In fact, some of the deadliest plants in the garden are also a source of important medicines, such as Taxus baccataor yew, used in the treatment of breast cancer.
A Catharanthus roseusknown as vinca and very common in gardens and parks, also has a double side.
Its components can be potentially fatal, as they interfere with fundamental processes of cell division. But, in the hands of chemistry and medicine, this same toxicity is transformed: isolated and refined, some of its alkaloids have become essential tools in the fight against cancer.
I and Digitalis purpureapopularly known as foxglove or digitalis, is a garden flower that is as beautiful as it is dangerous. Contains substances that, in the right dose, regulate heartbeat; in the wrong dose, they can stop them.
Digitalin was isolated from foxglove, one of the first effective compounds used in the treatment of certain heart diseases — and, even today, its derivatives are still present in modern cardiovascular pharmacology.
None of this, however, reduces its danger. Both plants that heal and those that do not have medicinal uses continue to be toxic — something very present in everyday life in the Jardim dos Venenos.
As head gardener Robert Ternent explained to the BBC, the team adopts several security measures.
“In some sites it is not necessary to take any precautions, while in others — such as the invasive giant parsley site — it is necessary to wear a full protective suit, mask and gloves.”
Some plants require extreme measures. THE Dendrocnide moroidesknown as gympie-gympie, is housed in a glass display case and even has an exclusive caregiver, because even slight contact with the plant can cause extreme pain.
“It has small hairs. If someone touches it and there is contact with the skin, these hairs dig into the skin and inject venom, causing what has been described as the sensation of being electrocuted and burned at the same time.”
A simple touch can leave victims suffering for weeks or even months.
It is one of the defense mechanisms of the plant world, which also includes the release of gases such as cyanide when animals chew certain plants or when gardeners prune them — the case of Prunus laurocerasus, known as cherry laurel or English laurel.
Jardim dos Venenos also includes a drug education program. He cultivates what Smith describes as “the ABCs of drugs”: opium poppies, a class A drug; cannabis, a class B drug; and Catha edulis, popularly known as khat, a class C drug.
Thus, behind those macabre gates, in the shadow of a historic castle, a garden full of stories flourishes which, despite being the most lethal in the world, is still beautiful.
