Known by many names, the Mexican prickle-poppy is also called argemony (with all four syllables stressed), the thorn-apple (not to be confused with the daturas or jimsonweeds), goatweed, cardo santo, cardo amarillo, chicalote and herbe a femme. Seeds were first cataloged back in 1592.
Thomas Jefferson wrote about planting seed for this curious plant, noting the first flower on June 18, 1767. A month later, he reported a second bloom (all told, there were four that year). But Jefferson could never have imagined what the future held in store for the prickly poppy.
The scientific name is Argemone mexicana (the genus referring to the Greek word “argema,” meaning “cataract of the eye,” because at one time the juice of the plant was used to treat such disorders). There are about 40 species of these annual or perennial herbs (and one shrub), native to North and South America and Hawaii. They belong to the great poppy family, or Papaveraceae. Originally an American native, the plant is now a pantropic weed, having spread throughout the tropical and subtropical places of the world. It’s been naturalized in Brazil, Hindustan and Africa, and amazingly, seed has even made its way to India, where it’s called sialkanta or phirangi dhatura.
When pressed, the round, blackish-brown seeds yield a pale-yellow latex ooze that becomes argemone oil. A minor, semi-drying oil, it contains (among other alkaloids) two highly toxic substances: sanguinarine and dihydrosanguinarine. Ingested in sufficient quantity, they can produce vomiting, diarrhea, loss of vision, fainting and (unless the victim receives immediate medical attention) coma, followed by death. The latex is also considered a narcotic.
In India, unscrupulous wholesalers of rapeseed-mustard oil have sometimes used argemone as an adulterant. In September 1998, following a round of food poisonings in Delhi in which some 60 people died, the Canadian government warned its citizens not to consume any mustard oil, mustard-seed oil, or foods containing them, as they could be adulterated with argemone.
In India, meanwhile, an argemone detection kit has been developed that uses a fluorescent chemical to detect the presence of argemone oil in mustard oil with a sensitivity of 0.01 percent.
As with opium poppies, of course, the plants grown in a garden setting would be hard put to injure, much less kill, the folks who grow them. It takes hundreds of plants, plus very scientific processing, to produce enough poison to be dangerous. And believe me, once you spot the spines on this plant, you know it’s not to be taken lightly.
Sow the seeds directly into the ground where you want the plants to grow as they, like all poppies, have a long taproot that does not take to transplanting. Soil fertility can be low, but good drainage is a must. Seeds will germinate in the cool weather of fall or in early spring, forming lovely rosettes of an intense silvery blue.
As spring passes into summer, 2- to 3-foot stems appear from the center of the plant, which bear the large, bright-yellow blossoms.