Thorn-apple, Datura stramonium.
Some Like It Hot
Hot summers like this one can be good for plants from warmer climes such as Thorn-apple, Datura stramonium.
Thorn-apple is a spectacular annual plant with large, dull green leaves with irregular jagged teeth. It can grow up to 1.5 metres (five feet) tall and the leaves have a satin texture and an unpleasant smell when crushed (note 1).
Thorn-apple plants have beautiful white trumpet-shaped flowers. These open at night and by late the following morning have usually closed up again. The flowers are followed by the spiny seed capsules that give the plant its English name. The seed capsules dry and split open to reveal masses of black seeds. Dried stems and seed capsules can persist through the winter (note 2).
Thorn-apple, Datura stramonium, with a flower bud and the spiny seed capsule that gives the plant its English name.
Shades of Night
Datura stramonium belongs to one of my favourite plant families, the Solanaceae (Nightshade family).
The Solanaceae contains plants that provide us with good food: these include potatoes, tomatoes, aubergines (eggplant, if you’re in the United States), peppers and chillies. But the family’s other claim to fame are some of the interesting chemicals (alkaloids) which the plants produce as secondary metabolites (note 3). Well-known examples include nicotine (an addictive drug found in tobacco plants, Nicotiana), solanine (a toxin found in green potatoes) and capsaicin (responsible for the heat of chillies).
A child of the late sixties and seventies, I grew up with Keble Martin’s Concise British Flora in Colour and there was something fascinating about Plate 61, which featured the Solanaceae. I looked longingly at the book, hoping to find these strange plants one day. Henbane (which I wrote about in February 2012) was illustrated, as were Bittersweet (Solanum dulcamara) and Deadly Nightshade (Atropa belladonna) but Thorn-apple wasn’t. Nonetheless I longed to see a plant with “fruit covered with spines, very poisonous” and such a memorable name.
I eventually saw my first Thorn-apple on an allotment neighbour’s compost heap and since then I’ve seen plants in other parts of Norfolk, including on a roadside near Dereham (2018), in a garden with free range hens not far from Wells-next-the-Sea (2020) and on a farm muck heap not far from Blickling (2021).
Datura stramonium is one of the more toxic members of the Solanaceae and contains atropine, hyoscyamine and scopolamine (note 4). These alkaloids are anticholinergics, blocking the action of acetylcholine, one of the body’s neurotransmitters.
Thorn-apple on a muck heap, September 2021
Hens amongst Thorn-apple. The seeds are sometimes used as bird food.
A Casual Alien
Most records of Thorn-apple come from waste ground, rubbish tips, cultivated and disturbed ground. It usually occurs as a casual alien (note 5) but it can persist and even reappear after long periods from dormant seeds. The seeds can be brought in via bird seed, and wool and soybean waste. My allotment neighbour kept racing pigeons and his plant came from their food.
Datura stramonium in the British Isles is far from its native home, thought to be the southern United States and Central America, although the Online Atlas of the British and Irish Flora says that its “Native range [is] unknown, possibly America or the Black Sea region”. Thorn-apple was cultivated in Britain by 1597 and grown commercially for alkaloids used to treat asthma. It was first recorded in the wild in 1777.
The Garden Organic website has lots of useful information about Thorn-apple’s lifecycle under British growing conditions. Seeds germinate from May to August, with a peak in May. Cultivation of the soil exposes seed to light and, together with the removal of volatile dormancy-inducing metabolites, this triggers germination. After flowering, the seeds are mature around 30 days after pollination and the seed capsule is ready to split open just 20 days later.
In good growing conditions (such as on my neighbour’s compost heap) a single plant can produce fifty or more capsules, each containing 600 – 700 seeds, giving a total of 30,000 seeds per plant. Seeds can remain viable in the soil for thirty years.
In my experience, however, most plants produce far fewer seed capsules and they are limited by competition from other plants and a lack of bare soil, as well as our climate. Thorn-apple plants are killed by frosts and prefer hotter summers.
The seedlings have a very distinctive appearance and are easy to pull up or hoe out. The RHS suggests wearing gloves when handling Thorn-apple, or washing your hands after touching it. Plants can be composted, but don’t include the seeds if you don’t want offspring.
Not To Be Eaten
Enjoy looking at Thorn-apple: it’s lovely. But don’t try to eat it.
Norfolk’s Eastern Daily Press gave a sensible, fact-based answer to a question from a reader from Toftwood, Dereham who had Thorn-apple growing in her garden (“Thorn-apple, Datura stramonium: This weed is not persistent.“) But a Daily Mail Reporter couldn’t resist writing about how the “Deadly and hallucinogenic Amazonian plant shoots up in British garden… after bird ‘drops seed’” (note 6).
Very small Thorn-apple seedlings.
Larger Thorn-apple seedlings: now easy to recognise.
“Hallucinogenic” is right, though, if you do eat any part of the plant. And “deadly” too, if you eat too large a quantity. (A given plant’s toxicity will depend on its age, where it is growing, and the local weather conditions.)
Although Datura stramonium has a long history of use as a herbal medicine (including treating asthma, worms, toothache and dandruff), it is very poisonous and the Plants For A Future website advises that it should only be used medicinally with extreme caution and only under the supervision of a qualified practitioner.
Consuming Thorn-apple can lead to an “intensely unpleasurable” experience and even death. Symptoms include visual distortions, dizziness and unavoidable hypnotic sleep (note 7). Within an hour of consumption, the mouth becomes dry, the pupils of the eyes dilate and the skin becomes flushed, followed by nausea, drowsiness and a rise in temperature. Higher doses can result in agitation, rapid heartbeat and hallucinations, followed by delirium, convulsions, coma and sometimes death. Visual disturbances can last up to two weeks (note 8).
Jimsonweed
Datura stramonium owes its common North American name – Jimsonweed – to a famous poisoning incident. “Jimson” is a corruption of Jamestown, the first permanent British settlement in the Americas and the site of Bacon’s Rebellion in 1696.
British soldiers sent to stop the rebellion were served a salad containing large quantities of Datura leaves. The leaves must have been bitter but they ate them and the result was “a very pleasant Comedy; for they turn’d natural Fools upon it for several Days: One would blow up a Feather in the Air; another wou’d dart Straws at it with much Fury; and another stark naked was sitting up in a Corner, like a Monkey, grinning and making Mows at them; a Fourth would fondly kiss, and paw his Companions, and snear in their Faces, with a Countenance more antick, than any in a Dutch Droll.”
The effects lasted eleven days, after which the soldiers “return’d to themselves again, not remembring any thing that had pass’d.” (note 9).
In 2004 a Danish man sold “Witches’ Brew” on the streets of Valencia in Spain, saying people who tried it would “see everything differently”. He was right (factually, if not morally), for those gullible enough to try it experienced hallucinations, accelerated heartbeat and other health problems and five people ended up in hospital. In the same year, two teenagers near San Diego in the United States took Jimsonweed as a prank while on a camping trip and died as a result of accidents while under its influence (note 7).
More recently, in 2019, over 200 cases of Datura stramonium poisoning, including five deaths, occurred in north-east Uganda. A batch of corn-soy food given to villagers as humanitarian relief contained soya beans grown in Turkey and contaminated with Datura stramonium seeds (note 10).
First hand accounts of consuming Datura stramonium give no doubts about the unpleasant effects, as users’ experiences on the WebMD website testify:
- “A living nightmare that lasts for days. Creepy, terrifying and disturbing visions that are in no way pleasant or enlightening. Not having a grasp of reality at it worst. After, 35 years, it still makes me shudder… DON’T DO IT!”
- “I don’t remember much except horror for the next 12 hours or so. It made me very sick, and oh boy, I felt like my brain was just not working for days after, like the absolute worst hangover you could ever get.”
- “This almost killed me, This drug sucks.”
Datura comes from the Hindi and ultimately Sanskrit names for another species, the Indian Thorn-apple, Datura metel (note 11).
The specific name, stramonium, may come from the Greek words for “nightshade” and “mad“. Other English names include “Devil’s Snare” and “Devil’s Trumpet”.
Grow Your Own
If I haven’t put you off, growing various species of Datura (including Thorn-apple) is very easy and rewarding if you have a sunny spot. I grow Datura stramonium (which I let self-seed) and this year its relative Datura innoxia is growing in pots on my patio. It has soft spines on its seed capsules, unlike those of Thorn-apple, hence innoxia, meaning “not noxious” (though it is just as toxic).
Datura seeds are available online, such as from Chiltern Seeds.
If you fancy something a bit bigger, the various species of Brugmansia (Angel’s Trumpets) are tender shrubs with trumpet-shaped flowers like a larger version of Datura. They are beautiful and just as toxic and grow well in large containers. There are seven species (and several hybrids) of Brugmansia but all are only known from cultivation. They were originally classified by Linnaeus as Datura arborea.
Notes
Note 1 – The leaves of Thorn-apple’s close relative, Datura innoxia, have a smell “similar to rancid peanut butter” when crushed. Datura stramonium leaves have the same strange and not particularly pleasant smell.
Note 2 – The white-flowered form of Datura stramonium has green stems but varieties occur with purple stems and flowers that are pale blue (var. chalybaea) or white with a hint of purple. There is also a form with spineless seed capsules, var. inermis. I have only seen the “normal” white-flowered form with spiny seed capsules.
Note 3 – A secondary metabolite is “a compound produced by an organism that isn’t directly involved its normal growth, development or reproduction. Instead, they generally mediate ecological interactions, which may produce a selective advantage for the organism by increasing its survivability or fecundity“. Secondary metabolites can, for example, make plants less palatable to herbivores or less susceptible to attack by fungi.
Note 4 – These are the main three alkaloids. The paper “Pharmacological properties of Datura stramonium L. as a potential medicinal tree: An overview” (by Soni P, Siddiqui AA, Dwivedi J, Soni V (2012), Asian Pac J Trop Biomed. Vol 2, pp1002 – 1008) lists over sixty tropane alkaloids.
Note 5 – Casual alien plants are species that “may flourish and even reproduce occasionally outside cultivation in an area, but that eventually die out because they do not form self-replacing populations, and rely on repeated introductions for their persistence“.
Note 6 – The headline is ridiculous but the article is largely factual. It warns that Thorn-apple can “create an inability to differentiate fantasy from reality”. This can also be caused by repeated exposure to certain British newspapers.
Note 7 – Described in “Poisonous Plants – A Cultural and Social History” by Robert Bevan-Jones (Windgather Press, Oxford, 2009), pp139 – 142.
Note 8 – From “Poisonous Plants and Fungi – An Illustrated Guide” by Marion Cooper and Anthony Johnson (HMSO, 1994), pp77 – 78.
Note 9 – From “The History and Present State of Virginia, In Four Parts” by Robert Beverley. The text has been extracted to the Documenting the American South website. The book has recently been reissued by the University of North Carolina Press, with an introduction by Susan Scott Parrish.
Note 10 – Mutebi, R.R., Ario, A.R., Nabatanzi, M. et al. “Large outbreak of Jimsonweed (Datura stramonium) poisoning due to consumption of contaminated humanitarian relief food: Uganda, March–April 2019.” BMC Public Health Vol 22, p623 (2022).
Note 11 – Most of the nine to fourteen species of Datura are native to Central America, especially Mexico. But Datura ferox occurs in China, D. metel in India and Southeast Asia and D. leichardthii in Australia. All three species are now thought to be early introductions from Central America.
This is not as improbable as it may seem: Sweet Potato, Ipomaea batatas, was also transported from the Americas to Polynesia, reaching the Cook Islands by 1210–1400 CE.
Postscript, December 2022
In mid December 2022 Food Standards Australia New Zealand (FSANZ) recalled ‘Riviera Farms’ branded baby spinach products after over 160 people across New South Wales, Australian Capital Territory, Victoria and Queensland suffered symptoms including delirium, hallucinations, rapid heartbeat and blurred vision, with many seeking medical treatment.
An investigation showed that the recalled spinach products were sourced from one producer, with the spinach all located in one field.
Having read this blog post, you’ll already have worked out what caused the mass poisoning: “Weed responsible for hallucinogenic spinach recall identified as thornapple“.
