Humans have tied certain plants to death for thousands of years, and the reasons fall into two groups: what a plant looks like or where it grows, and what it does to the body. Some death plants are purely symbolic, while others earned their reputation by killing people and animals. The most striking cases are both, honoured at graves and also among the most poisonous plants in a garden.
Why Some Plants Became Symbols of Death
Long-lived evergreens came to stand for death and eternal life at once. The Mediterranean cypress has carried meaning for people since at least the third millennium BCE, from ancient Sumer, Egypt and Persia through Greece, Rome, Islamic empires and Western Europe.1Economic Botany. The Ethnobotanical Evolution of the Mediterranean Cypress (Cupressus sempervirens) In Britain the yew is closely tied to churchyards and death rites.2Sydney Studies in Society and Culture. Scotland’s Sacred Tree: The Fortingall Yew Its dark, sombre look and its poison suggested death, while staying green all year made it a symbol of immortality.3Sydney Studies in Society and Culture. Scotland’s Sacred Tree: The Fortingall Yew Yew wood was once used in magic and fortune-telling too, such as divining wands.4Sydney Studies in Society and Culture. Scotland’s Sacred Tree: The Fortingall Yew The dense foliage of yews and cypresses casts deep shade, which made them feel solemn and fitting for places of mourning. Yews can live through many human generations, so they seemed to belong to time beyond a single life.
Yews and cypresses are still planted near graves in many countries because of these meanings. A very old churchyard yew may even be older than the church beside it.
Flowers carry these links too. In ancient Greece the asphodel was tied to the afterlife and sacred to Persephone, queen of the underworld, because it grew on tombs and some ancient grave inscriptions mention it.5Greek, Roman, and Byzantine Studies. Homer’s Asphodel Meadow In the Victorian language of flowers the marigold often meant grief, a puzzle even then given its bright colour.6Grave Matters. Life is a Flower: Memory and Memorial in the Language of Flowers A plant’s meaning often grows from where it is seen: asphodel flourished in rough ground and on tombs, so people linked it with the dead. Marigold’s meaning came from the Victorian habit of assigning set meanings to flowers, written down in popular guidebooks.
Asphodel and marigold earned their meanings through custom, not by killing. Yew is the rare case where the symbol and the danger are both real, so a plant’s meaning is no guide to whether it is safe.
Funeral Flowers and What They Mean Today
Lilies are the most popular funeral flower.7Peachtree Petals. Funeral Flower Meanings: Why We Have Flowers at Funerals They represent innocence restored to the soul after death, and white lilies mean purity and sympathy.8Peachtree Petals. Funeral Flower Meanings: Why We Have Flowers at Funerals For Christians they carry extra weight because of a tradition that Mary’s tomb was covered in white lilies.9Peachtree Petals. Funeral Flower Meanings: Why We Have Flowers at Funerals
Lilies do have a serious catch: they are highly toxic to cats, and even pollen or vase water can cause kidney failure. If the family has a cat, pick another flower, since pollen dropping onto furniture or fur is enough risk.
The Truly Deadly Plants and How They Kill
Many of these plants contain alkaloids, natural plant chemicals that act strongly on the body. Many resemble the body’s own chemical messengers. Because they fit into the same receptors or channels that nerves and heart cells use, tiny amounts can change how those cells behave. Because they target different receptors and channels, poisons from different plants can produce very different effects, from racing hearts to paralysis. Not every plant poison is an alkaloid, though; ricin, for instance, is a protein and works in a completely different way.
Several of these poisons attack the heart’s electrical system. Yew’s poisons block the channels heart cells use to fire, which can cause the heart to fail.10PubMed Central. Cardiogenic shock due to yew poisoning rescued by VA-ECMO: case report and literature review Every part of oleander contains heart poisons that can trigger dangerous irregular heartbeats and death.11PubMed. Investigation of cardiac glycosides from oleander in a human induced pluripotent stem cells derived cardiomyocyte model Monkshood’s poison, aconitine, holds sodium channels in heart and nerve cells open so the cells cannot reset.12Wikipedia. Aconitine The heart can then fall into fast, chaotic rhythms, and death comes from heart or breathing failure.13Wikipedia. Aconitine Foxglove contains similar heart chemicals, and is the source of the drug digoxin.
Poisoning by yew, oleander, monkshood or foxglove can therefore look similar at first, with nausea, dizziness and an abnormal pulse. Cooking, drying or dead plant material does not necessarily remove the danger, and yew stays toxic after it is clipped and wilted.
Others work on nerves and muscles. Deadly nightshade contains atropine, hyoscyamine and scopolamine in every part, most in the ripe berries and green leaves.14PubMed Central. Atropa Belladonna intoxication: a case report These block a key nerve signal, causing a hot, dry, confused, fast-heartbeat state.15PubMed Central. Atropa Belladonna intoxication: a case report With that signal gone, the mouth dries, the skin flushes, the pupils widen and the pulse speeds up, and confusion and hallucinations can appear. Large amounts can lead to coma and death.16PubMed Central. Anticholinergic Toxic Syndrome Caused by Atropa Belladonna Fruit (Deadly Nightshade): A Case Report
Poison hemlock causes paralysis that spreads from the limbs inward, and Socrates’ execution in 399 BCE is usually blamed on it.17PubMed. What killed Socrates? Toxicological considerations and questions Some details in ancient accounts of his death don’t fully match what hemlock poisoning looks like, however.18PubMed. Death of Socrates: a likely case of poison hemlock (Conium maculatum) poisoning South American curare, from forest vines, paralyses muscles by blocking nerve signals and was used on hunting arrows.19Journal of the Royal College of Physicians of Edinburgh. Curare: the South American arrow poison
Castor bean kills cells directly. Its main poison is ricin, a protein.20Preprints. Ricin: An Ancient Story for a Timeless Plant Toxin Ricin disables the cell’s protein-making machinery and damages its genetic material, so cells die.21PubMed Central. Ricin: An Ancient Story for a Timeless Plant Toxin Chewed seeds are the danger, and the plant is common in gardens for its striking leaves.
Exposure often comes from how these plants look. Shiny nightshade berries look edible, a risk for children. Yew’s red berries tempt children too; the flesh is less dangerous than the seed inside and the needles. Foragers mistake hemlock for wild parsley, carrot or parsnip. Oleander is a common hedge in warm climates, and all of it is poisonous.
Why Plants Make Poisons at All
Plants have evolved a huge range of chemical defences that are toxic, repellent or hard to digest for plant-eaters.22Annual Review of Plant Biology. Plant Defense Against Herbivores: Chemical Aspects Some are always present, while others are made only after the plant is attacked.23Annual Review of Plant Biology. Plant Defense Against Herbivores: Chemical Aspects Plants and insects are thought to be locked in an arms race, with plants making new poisons and insects evolving resistance.24PubMed Central. Plant Insecticidal Toxins in Ecological Networks Humans get caught by chemicals aimed mostly at insects and grazing animals.
Many plant poisons target basic machinery shared by most animals, such as nerve signalling or protein production. The plant did not evolve to harm people specifically, so our danger is a side effect.
Plants often concentrate poison in the seeds, leaves or berries they most need to protect. Some animals tolerate a poison that harms humans, so a plant being eaten by wildlife is no sign it is safe for people.
What To Do if Someone Eats a Poisonous Plant
Call poison control or emergency services immediately, even if the person seems fine. Some plant poisons act after a delay, so the first hour can look normal while the poison is still being absorbed. Early treatment has more options than late treatment.
Have these ready for the call: the person’s age and approximate weight, since danger depends heavily on body size; what was eaten, which part, and roughly how much, even if you are unsure; when it happened; and any symptoms you can see. Keep a sample or photo of the plant to hand so doctors know what they’re treating. Follow the instructions you are given, which may mean going to hospital or staying put and watching.
While you wait, remove any remaining plant from the mouth and note the time eaten. Don’t make the person vomit unless poison control says so, and don’t give home remedies.
An antidote, a treatment that reverses a specific poison, exists for only a few plant poisonings.25PubMed Central. Poisoning by Plants Physostigmine for nightshade-type poisons and antibody treatment for foxglove are two examples.26PubMed Central. Poisoning by Plants The foxglove antibodies are first-line care for severe cases with dangerous heart rhythms or shock.27PubMed Central. Acute Plant Poisoning and Antitoxin Antibodies Most plant poisonings, though, are treated by supporting the body while the poison clears. In severe yew poisoning, patients have survived after a heart-lung machine kept their blood moving.28PubMed Central. Taxine alkaloid poisoning successfully supported with venoarterial extracorporeal membrane oxygenation: a case report
Keeping Children, Pets and Livestock Safe
Most livestock poisonings happen in early spring or during drought, when feed is short.29University of Minnesota Extension. Plants poisonous to livestock Hungry animals eat plants they would normally ignore.30University of Minnesota Extension. Plants poisonous to livestock Keep good feed available, supplying hay in those periods, and check pastures for yew or hemlock. Yew clippings tossed over a fence are a classic cause of livestock deaths.
In your own garden, identify plants by name, using a reliable app or a nursery. Oleander, foxglove, monkshood, yew and castor bean are all common ornamentals. Fence or remove them where toddlers play, and wear gloves when handling monkshood, whose poison can pass through skin.
Teach children never to eat berries, seeds or leaves without an adult, and explain that bright or shiny doesn’t mean safe. Keep the poison control number saved in your phone.
When a Deadly Plant Becomes Medicine
Extracts of Pacific yew bark proved toxic to living cells, and the strongest compound was named paclitaxel.31National Cancer Institute. Discovery: Natural Compound Offers Hope Paclitaxel stops cancer cells dividing by freezing their internal scaffolding.32PubMed. Camptothecin and taxol: historic achievements in natural products research The effect that harms a grazing animal’s cells can be useful against cancer cells, which divide rapidly. Approved in 1992 for ovarian cancer, it is now used for breast and lung cancers too.33PubMed. Camptothecin and taxol: historic achievements in natural products research Because it can also harm healthy dividing cells, it is given under close medical supervision.
Curare’s paralysing action helped scientists understand nerves and muscles,34PubMed. How studies on curare contributed to the development of neurophysiological research in Brazil and curare-type drugs are used to relax muscles during surgery. Foxglove gave us digoxin. Digoxin treats heart failure, but an overdose causes the same poisoning as foxglove. Garden foxglove is never a safe homemade source, since potency varies widely.