Weeds With Spiny Seed Pods

Thorn apple is a weed that prefers a warmer climate than Britain, but in hot summers they are quite commonly found. Another common name, devil's snare, sounds alarming, but a few simple precautions will enable gardeners to handle this weed without great risk. Appreciate this witchy weed’s beautiful blooms and spiky seedpods, but beware. Its notoriously toxic seeds and leaves can cause convulsions, hallucinations or even death, and climate change is making its poisons even more powerful. Datura, a night-blooming flower sometimes raised in home gardens, is also known as Jimsonweed or Thornapple (Datura stramonium). Jimsonweed is a contraction of Jamestown and is the name that early settlers and British soldiers gave the plants. Thornapple is an appropriate common name because it aptly describes the …

Datura stramonium (thorn apple)

Thorn apple is a weed that prefers a warmer climate than Britain, but in hot summers they are quite commonly found. Another common name, devil’s snare, sounds alarming, but a few simple precautions will enable gardeners to handle this weed without great risk.

Quick facts

Latin name Datura stramonium
Common name Thorn apple
Life cycle Annual
Areas affected Uncultivated ground, beds, borders

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What is Datura stramomium

Datura stramonium (or thorn apple as it is commonly known) is an annual weed of gardens, roadsides and other waste or cultivated land. It is widely naturalised in warmer countries throughout the world, and is quite common in the British Isles, often appearing in waste and cultivated ground.

Although quite a striking plant, it is as well to be aware that all parts, particularly the seeds, are highly poisonous. It belongs to Solanaceae, a family which includes the potato and tobacco, and many members of this family contain toxic substances. This page looks at options for gardeners when Datura stramonium is becoming a problem.

Appearance

This weed can grow to heights of 1m (3¼ft). It flowers from July to October with wide, funnel-shaped flowers. These are usually white but plants with purple or lilac flowers and purplish stems are referred to as Datura stramonium var. chalybaea (syn. D. stramonium var. tatula).

It produces seedpods which are large and spiny (hence the common name thorn apple) though plants with spineless seedpods are known and these are referred to as D. stramonium var. inermis.

The leaves very broad and coarsely toothed.

The problem

The potentially harmful poisonous and hallucinogenic properties of this plant can sound alarming especially when made much of in the media. The leaves and seed pods also look exotic and alien. In fact this is quite a small plant and not very invasive in Britain. Common sense precautions limit risk factors so that gardeners need not be too alarmed by this weed.

The seed appears to retain its viability for many years when buried and germinates when the soil is disturbed. Spread is facilitated by human activities – in gardens it appears to be a contaminant of birdseed.

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Control

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.

Cultural control

There are a number of non-chemical control options.

Dig, pull or hoe out plants before seed is set. Seedlings and plants that have not set seed can be added to the compost heap where the toxins will naturally break down. However, plants that have set seed should be consigned to the green waste collection, buried deeply (60cm/2ft or more) or burnt in order that the seed does not disperse in the garden or persist in the compost heap. Always wear gloves or thoroughly wash hands after handling this plant.

Use a mulch of organic matter, at least 5cm (2in) thick or opaque sheeting, such as woven polypropylene, to smother this weed.

Weedkiller control

Contact herbicides such as acetic acid (eg. Weedol Gun! Fast Acting, Roundup Speed Ultra, Spot On Fast Acting Weedkiller or Resolva Fast Weedkiller), fatty acids (eg. Job Done Garden Ultrafast Weedkiller) and pelargonic acid (eg. Doff 24/7 Fast Acting Weedkiller, Roundup NL Weed Control or Resolva Xpress Weedkiller) are good at knocking back young annual weeds such as thorn apple. Systemic herbicides such as glyphosate (e.g. Roundup Fast Action, SBM Job done General Purpose Weedkiller or Doff Advanced Concentrated Weedkiller) will also be effective and can be used when mature plants need to be eliminated.

These herbicides are non-selective and so care should be taken while spraying near other plants. Plants to be avoided can be covered with a bucket/flowerpot or screened with plastic when spraying.

Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.

Download

Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 3a and 4)

Weed of the Month: Jimson Weed

Jimson weed (Datura stramonium) is a beautiful, witchy plant that begins blooming in late summer and continues through the first frost. A member of the notorious nightshade family, its more famous cousins include tomato, eggplant, pepper, tobacco, and potato. Most members of this plant family are poisonous, and jimson weed is no exception. All parts of the plant are toxic, most particularly the seeds. Potent amounts of alkaloid compounds are present, which potentially cause convulsions, hallucinations, and even death if ingested. And as climate change increases the amount of carbon dioxide in the air, studies have found that the toxicity of plants like jimson weed only increases.

The genus name Datura comes from the Hindi word for the plant, noteworthy since most botanical names are derived from Latin or Greek. The origins of the plant itself are contested—every source I checked listed a different native origin, ranging from Mexico to India, and it now grows all over the world. Not surprisingly, it has found its way into many cultural and medicinal traditions. Ayurveda, traditional Chinese medicine, and Native American shamanistic practices all employ jimson weed medicinally or ritualistically. Its seeds and leaves are used as an antiasthmatic, antispasmodic, hypnotic, and narcotic.

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Having grown up in Virginia, I was intrigued by one of the common names I saw recurring in my plant books—Jamestown weed—and researched the origins. One story simply connects the first New World observations of the plant to settlers in this early Virginia colony. A more famous tale tells of the plant’s accidental ingestion by some British soldiers sent there to suppress Bacon’s Rebellion in 1676. After eating some in a stew, the soldiers spent 11 days in a hallucinatory stupor, blowing feathers, kissing and pawing their companions, and making faces and grinning “like monkey[s].”

Jimson weed’s white to purple blooms are fragrant at night, attracting moths and other nocturnal pollinators, a common trait in white-bloomed plants. The rest of the plant, however, is stinky! Crush and sniff the oaklike leaves, and you’ll understand why domesticated and wild animals avoid eating this plant—it smells a bit like feet. Indeed, accidental poisonings tend be more common among humans than among other animals.

Though the trumpet-shaped flowers are stunning, my favorite part of the plant is the devilish-looking seedpod. The size of a Ping-Pong ball and covered in spikes, the seed capsule splits into four parts like a monster’s maw, revealing the dark brown seeds inside. In the winter you might notice its tall, dry stalks bearing the prickly seedpods, which to me look like the scepter for a demon. With all its extraordinary looks and lore, jimson weed is a fascinating plant to contemplate (but maybe not cultivate)!

The Weed of the Month series explores the ecology and history of the common wild plants that most gardeners consider weeds.

Browse the Weed of the Month archives >

Saara Nafici is the executive director of Added Value/Red Hook Community Farm. She is also the former coordinator of the Garden Apprentice Program at Brooklyn Botanic Garden and a longtime activist, feminist, bicyclist, naturalist, and youth educator. Follow her weedy plant adventures on Instagram.

What Weed Has a Round Prickly Seed Pod?

Datura, a night-blooming flower sometimes raised in home gardens, is also known as Jimsonweed or Thornapple (Datura stramonium). Jimsonweed is a contraction of Jamestown and is the name that early settlers and British soldiers gave the plants. Thornapple is an appropriate common name because it aptly describes the round, prickly seedpod that develop after the spent flowers fall off the plant. The prickly seedpods prevent animals from eating the toxic seeds.

Description

Jimsonweed grows to heights of between 1 and 5 feet. Its leaves’ edges are toothed edges and nearly egg shaped with pointed ends. Their length ranges from 2 to 8 inches. Funnel-shaped flowers are 2-1/2 to 4 inches long and open to a trumpetlike bell in white, violet or lavender. The plant’s fruit is a spiny pod measuring roughly 2 inches in diameter. The seedpods grow as they ripen and the seeds mature. Ripe seedpods burst open, scattering the seeds.

  • Jimsonweed grows to heights of between 1 and 5 feet.
  • Its leaves’ edges are toothed edges and nearly egg shaped with pointed ends.
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Datura Species

Most species are low-growing, shrublike or spreading perennials or are prolifically reseeding annuals. D. wrightii is the species that is common to the Western United States. Rank-smelling leaves and large, white flowers that are occasionally tinged with purple characterize this plant. A sprawling perennial, the plants have enormous taproots that may extend deeper than 2 feet into the ground. Its geographic range extends from California to Utah, Arizona, New Mexico and into Texas. D. wrightii is considered a cosmopolitan annual weed that seeds prolifically. D. discolor is a native species found in riverbeds and desert washes in Arizona and southeastern California. It has smaller flowers. D, stramonium is naturalized throughout the United States. D. stramonium is distinguished from D. wrightii because the plants have smaller flowers and a more erect growing habit.

  • Most species are low-growing, shrublike or spreading perennials or are prolifically reseeding annuals.
  • D. discolor is a native species found in riverbeds and desert washes in Arizona and southeastern California.

History

The contraction of “Jamestown weed” is the origin of the name Jimsonweed. Soldiers and settlers were poisoned after eating the plant’s leaves in salads. Long ago in India and Russia, robbers would grind up the seeds of Jimsonweed and mix them with water as a way to sedate, induce amnesia or daze people they intended to victimize and rob. Members of the ancient Indian religious order that worshipped Kali, the goddess of destruction, would also grind the seeds and feed them to people before robbing and/ murdering them. In China, Jimsonweed was prescribed for the sedative effects, for foot diseases and used for flatulence.

Toxic Effects

All parts of Datura or Jimsonweed are poisonous. Keep places where livestock graze free of the plant. Ridding an area of plants is difficult and time consuming because of the ease with which seeds spread. Some people may experience skin irritation from contact with these plants, so wear protective clothing or gear. Symptoms of Jimsonweed poisoning include blurred vision, confusion, dilated pupils, dry mouth, difficulty urinating, hallucinations and tachycardia. Although it rarely causes death, later signs of toxicity may include coma and seizures. Emergency medical attention is necessary in cases of suspected Jimsonweed poisoning. Poisoning is treated with activated charcoal and gastric lavage. Severe sinus tachycardia is treated with beta-blockers.