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weed with round thorny seed

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

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)!

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].”

There are several types of burr weeds, most of which can be found growing in a wide range of conditions and soil types. However, burr medic seems to favor poor soils, such as heavy clay. Like other trifoliate weeds, such as clover, burr weed has leaves that are grouped together in threes.

Therefore, you may want to use an old woolen blanket to drag over the area first, which should snag most of these burrs. Then the area can be treated with a pre-emergent, such as corn gluten meal, to prevent germination of any seeds left behind. Late summer or early fall is a good time to do this.

What is Burr Medic?

If your lawn is filled with prickly burrs, you likely have burr weeds. With a little vigilance, however, it is possible to control burr medic and improve the health of your lawn. Read on to learn more.

Burr medic (Medicago polymorpha), also known as burr weed, is a type of trifoliate weed that can quickly spread throughout the lawn and garden if not controlled.

Since burr medic spreads and reproduces by seed, the best way to control the weed is to remove it before it has a chance to set its seed, even better before it flowers.