THIS HOUSEPLANT COULD BE YOUR LAST - Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities - Amy Stewart

Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities - Amy Stewart (2009)


Some of the most popular houseplants are surprisingly toxic. They were chosen not for their suitability as a snack for pets and small children, but for their ability to thrive in a year-round climate of 50 to 70 degrees Fahrenheit. That’s why many houseplants are actually tropical plants that come from the jungles of South America and Africa.


The poinsettia, one of the most reviled indoor plants, is not nearly as toxic as its reputation would lead one to believe. As a member of the Euphorbiaceae family, the sap is mildly irritating, but that is the extent of it. While the poinsettia gets plenty of bad press around the holidays, many other houseplants escape notice in spite of their more toxic qualities.


Spathiphyllum spp.

A South American plant with simple white flowers that resemble calla lilies. In 2005 more people called poison control centers about possible peace lily poisoning than any other plant. (This may have more to do with how popular the plant is than how poisonous it is.) The plant contains calcium oxalate crystals that can bring on skin irritation, burning of the mouth, difficulty swallowing, and nausea.


Hedera helix

This ubiquitous European vine grows outdoors as a ground cover but is also one of the most popular indoor potted plants. The berries are bitter enough to discourage people from eating them, but they could cause severe gastrointestinal problems and possible delirium or respiratory problems. Sap from the leaves can cause serious skin irritation and blisters.


Philodendron spp.

An ivylike plant native to South America in the West Indies. All parts of the plant contain calcium oxalates. Nibbling on a leaf might only bring about mild burning in the mouth or a little nausea, but ingesting it could lead to severe abdominal pain, and repeated skin contact may cause serious allergic reactions. Poison control centers in the United States got over sixteen hundred calls in 2006 related to philodendron poisoning.


Dieffenbachia spp.

A tropical South American plant well known for its ability to temporarily inflame vocal cords, leaving people unable to speak. Some species are believed to have been used as an arrow poison in combination with other plants. Most poisonings involve severe irritation of the mouth and throat, swelling of the tongue and face, and stomach problems. The sap is also irritating to the skin, and can cause light sensitivity and pain if it gets in the eyes.


Ficus benjamina, F. elastica

These two indoor trees are closely related species in the mulberry family. The latex from these plants can provoke severe allergic reactions. One case history describes a woman who developed anaphylactic shock and other frightening symptoms that disappeared promptly after her ficus tree was removed from her home.


Euphorbia tirucalli

This African plant is not actually a cactus, but it gets its name from the long, skinny stems that resemble a succulent. Pencil cactus has become popular in modern interior design for its striking, architectural shape. But like other euphorbia, it produces a corrosive sap that causes severe rashes and eye irritation. It requires some pruning to keep it down to a reasonable size indoors, and gardeners are often surprised that a single pruning session can bring on such a painful reaction.


Solanum pseudocapsicum

Often sold as an ornamental pepper plant, it is actually more closely related to deadly nightshade. All parts of the plant contain an alkaloid that can bring on weakness, drowsiness, nausea and vomiting, and heart problems.



Deadly Nightshade


Professor and plant researcher Henry G. Walters speculated in 1915 about the potential for crossbreeding carnivorous and poisonous plants. He believed that if a poisonous plant had “the semimuscular system possessed by the carnivorous plants, it would be more dangerous than the cholera.” Dr. Walters declared that plants were capable of love and that they had memories, implying that they might also hold a grudge as lovers do. The deadly nightshade, he believed, was filled with hatred.


Shady, damp areas; seeds need uniformly damp soil to germinate

Europe, Asia, north Africa

Belladonna, devil’s cherry, dwale (an Anglo-Saxon word meaning “a stupefying or soporific drink”)

Although the entire plant is poisonous—just rubbing up against it can raise pustules on the skin—the blackberries are the plant’s most tempting feature. A Virginia farmer named Charles Wilson lost his children to those berries in 1880. The youngsters’ terse obituary suggests an agonizing weekend: “The first and youngest died last Thursday, the second, on Sunday night, and the third, and only remaining child, on Monday.”

Even today, tales of deadly nightshade poisoning appear in the medical literature. An elderly woman turned up at the hospital every fall in a kind of psychosis; doctors were unable to trace the cause of her hallucinations, delusions, and headaches. After several days, the symptoms would subside on their own. Finally, her daughter brought in a handful of berries from a shrub growing near her house. She had been snacking on deadly nightshade every autumn when the berries grew ripe but somehow managed to escape a fatal poisoning.

“Hot as a hare, blind as a bat, dry as a bone, red as a beet, and mad as a hatter.”

This is far from the only case: A couple earned their place in medical history by baking a pie of nightshade berries, mistaking them for the much more edible bilberries. In Turkey, a review of nightshade poisoning found that forty-nine children were sickened over a six-year period. Most ate the berries themselves out of curiosity, but at least one child was fed nightshade by his parents in the mistaken hope that it would treat his diarrhea.

Deadly nightshade performs its dark magic with the help of an alkaloid called atropine, which causes rapid heartbeat, confusion, hallucinations, and seizures. The symptoms are so unpleasant that atropine is sometimes added to potentially addictive painkillers to keep patients from getting hooked. Medical students memorize this simple mnemonic trick to help them recognize the signs of poisoning: “Hot as a hare, blind as a bat, dry as a bone, red as a beet, and mad as a hatter.” “Madness” in this case refers to meaningless speech, a sign of deadly nightshade poisoning.

The herbaceous perennial is found across Europe, Asia, and North America, where it flourishes in damp, shady spots. It grows to about three feet tall, producing pointed, oval-shaped leaves and purplish brown tubular flowers. From these flowers the bright black berries emerge, beginning as hard green fruit that ripen to red, finally reaching their full dark glory in the fall.

Early physicians mixed up a potent brew of deadly nightshade, hemlock, mandrake, henbane, opium, and other herbs as a surgical anesthetic. Atropine still has medicinal uses today and has been administered as an antidote to poisoning from nerve gas and pesticide exposure.

Italian women dropped mild tinctures of deadly nightshade into their eyes to dilate their pupils, which they thought made them more alluring. The name “belladonna” may come from this practice; it means “beautiful woman,” but the term might also originate from buona donna, a medieval witch doctor who treated the indigent with mysterious potions.

Atropa comes from one of the three Fates of Greek mythology. Each Fate had a role in determining human destiny. Lachesis measured the thread of destiny at birth; Clotho spun the thread, controlling one’s destiny; and then, at the end, Atropos brought death at the time and manner of her choosing. Milton remembered her this way:

Comes the blind Fury with the abhorrèd shears,
And slits the thin-spun life.

Meet the Relatives Member of the large and unruly Solanaceae family, which includes henbane, mandrake, datura, and the spicy Habanero chile pepper.



Death Camas


Several species of death camas thrive in meadows across the western United States. They are bulb plants with strappy, grasslike leaves and clusters of starry flowers in shades of pink, white, or yellow. The entire plant contains toxic alkaloids, and although the level of toxins may vary between species, it is safest to assume that they are all highly poisonous. Eating any part of the plant or the bulb will cause drooling or frothing at the mouth, vomiting, extreme weakness, an irregular pulse, and confusion and dizziness. In cases of severe poisoning, the final symptoms include seizures, coma, and death.



North America, primarily in the West

Black snakeroot, star lily

Death camas poisoning is a serious problem for livestock. Sheep tend to be drawn to the plant, especially in the early spring when there isn’t anything else to eat. If the ground is wet, they are often able to pull up the entire plant. There is no treatment for animals who have been sickened, and usually they are simply found dead.

Dietitian and food historian Elaine Nelson McIntosh recently discovered that death camas might have played a role in the terrible illnesses that members of the Lewis and Clark expedition faced. In September 1805 the group passed through the Bitterroot Mountains, a particularly difficult range of the Rockies. They were already desperately low on food and suffering from a variety of nutrition related ailments, including dehydration, sore eyes, rashes, boils, and wounds that would not heal. On September 22 the group managed to obtain some food from the Nez Perce tribe. It included dried fish and the roots of a similar plant, blue camas (Camassia spp.), both of which the men had eaten before with no problem.

Eventually Lewis and Clark’s team staggered on, facing a winter in which they would be forced to eat their dogs and take their chances with the roots of other unfamiliar plants.

Members of the group were beset with violent illness and suffered from diarrhea and vomiting. Lewis himself was seriously ill for two weeks. Dr. McIntosh believes that the men may have been inadvertently poisoned by eating death camas instead of the edible blue camas. The flowers would not have been in bloom at the time, making it difficult to distinguish the two, and even local Indians familiar with the bulbs could have made an honest mistake. The expedition came to a halt while the men recovered. Eventually they staggered on, facing a winter in which they would be forced to eat their dogs and take their chances with the roots of other unfamiliar plants.

Meet the Relatives Once classified in the lily family, death camas is now grouped into a family with other wild bulbs, many of them poisonous. Relatives include false hellebore (Veratrum album) and trillium (Trillium spp.).