Wicked Plants (11 page)

A popular, showy shrub in North America, Europe, and Australia. The long, bristlelike red stamens release golden pollen from the tips. The pollen is triangular in shape and lodges in the sinuses, making it a particularly vicious allergen.

This evergreen is a serious but overlooked source of allergens. The males produce cones, along with large quantities of pollen. Some junipers have both male and female organs on one plant (monoecious), which means that they might produce some berries but will also shed pollen.

One of the most popular grasses for lawns in the South and warm-weather climates throughout the world, it is also the most allergenic. It blooms steadily, and the flowers often grow so low that lawn mowers miss them. New varieties don’t produce any pollen at all, but older varieties are so problematic that some cities in the Southwest have banned them.

PUERARIA LOBATA

Kudzu to the rescue!” So proclaimed a 1937
Washington Post
article about the powers of this exotic vine to control erosion. And indeed, for almost a hundred years the vine enjoyed the enthusiastic support of American gardeners and farmers.

The Centennial Exposition, held in 1876 in Philadelphia, was a carnival of wonders. Roughly ten million Americans were introduced to the telephone, the typewriter, and a miraculous new plant from Japan: kudzu. Plant enthusiasts loved the flowers’ fruity, grapelike fragrance and the fact that the vine could scramble over a trellis so quickly

Soon farmers realized that livestock would eat the vine, making it a useful forage crop. Kudzu gripped the soil and stopped erosion. A government program encouraging the use of the vine gave kudzu all the encouragement it needed.

Kudzu had other plans for the South. The vine made itself at home, growing up to a foot per day during the warm, humid summers. This plant is born to run: Over two dozen stems emerge from a single crown, and each
of those vines can stretch to one hundred feet. A single massive tap root can weigh up to four hundred pounds. Each individual leaf can twist and turn so that it receives the maximum amount of sunlight, making the vine particularly efficient at harnessing the sun’s energy and keeping rays from reaching the plants below it.

Kudzu shrugs off cold weather and spreads by underground rhizomes and seeds, which can survive for several years before sprouting. It strangles trees, smothers meadows, undermines buildings, and pulls down power lines. Southerners say they sleep with the windows closed to keep it from sneaking into the bedroom at night.

The vine covers seven million acres in the United States. The damage it has caused is estimated in the hundreds of millions. At the Fort Pickett military base in Virginia, kudzu overwhelmed two hundred acres of training land. Even M1 Abrams battle tanks couldn’t penetrate the rampant growth.

But the South has not surrendered. Aggressive herbicide campaigns, controlled burns, and repeated slashing of new growth can keep kudzu in check. Southerners also fight back by eating the vine that is eating them: fried kudzu leaves, kudzu blossom jelly, and kudzu stem salsa all put a bad plant to good use.

Meet the Relatives
Kudzu is a legume; it is related to such useful plants as soybeans, alfalfa, and clover.

Who knew grass could be so dangerous? A lawn of wicked grasses could slice your skin with razorlike blades, close your throat with maddening pollen, get you drunk, and poison you with cyanide. One grass even acts as cremator, bursting into flames and sending its seeds and runners over the ashes.

The bright chartreuse blades grow to four feet tall, crowding out everything in their path. The edge of each blade is embedded with tiny silica crystals as sharp and serrated as the teeth of a saw. Roots can travel more than three feet deep, producing barbed rhizomes that pierce the roots of other plants and shove them out of the way in a sinister quest for world dominance.

Some botanists suspect that cogon grass contains a poison that kills its competition, but poison is hardly necessary: cogon grass’s weapon of
choice is fire. Thanks to its high flammability, it lures fire into a meadow and sets it loose on the competition, encouraging it to burn hotter and brighter than it otherwise would. (Just one spark from a power saw was enough to turn eight acres in Ocala, Florida, into a conflagration.) Then, like a phoenix rising from the ashes, fresh young cogon blades spring from the charred remains of the roots and grow stronger than ever after the cleansing inferno. When fire isn’t available, wind will do, too: one plant disperses thousands of seeds up to three hundred feet away.

Cogon grass found its way here in the 1940s, when the U.S. Department of Agriculture made the perplexing decision to plant it for erosion control and as grazing food for cattle—in spite of the fact that the grass contains little nutrition and was sharp enough to cut the cows’ lips and tongues. It thrives in the southern United States but has slowly made its way north.

A swamp-dwelling grass with sharp blades, widespread in the southe stern United States.

Found throughout North America; grows three to seven feet tall with sharp, toothed edges, earning it the charming nickname “ripgut.”

Invasive scourge of coastal California. Highly flammable and virtually impossible to kill. Each plant produces millions of seeds. Beautiful feathery plumes are often collected and carried off by naïve tourists, helping spread the seeds even farther.

A clumping, perennial grass that contains two major allergens responsible for the most severe forms of hay fever; grows throughout North America.

A popular choice for lawns and the cause of some of the worst suburban allergies.

An invasive weed throughout the United States that can reach eight feet tall. Young shoots contain enough cyanide to kill a horse. Death is mercifully swift, usually caused by cardiac arrest or respiratory failure and preceded by only a few hours of anxiety, convulsions, and staggering about.

An annual ryegrass that grows alongside cereal crops worldwide. It is often infected by a fungus that if accidentally eaten causes symptoms similar to drunkenness. Two thousand years ago Ovid described a farmer’s ruined fields this way: “. . . darnel, thistles, and a crop impure / Of knotted grass along the acres stand / And spread their thriving roots thro’ all the land.”

CNIDOSCOIUS ANGUSTIDENS

It sounds like the plot of a horror movie: A group of teenagers went hiking in the Mexican desert and came back with a mysterious rash. The next day, one girl went to the doctor complaining of red, itchy spots on her hand. She was prescribed some antihistamines, which should have done the trick. But the pain only got worse. In a few days, a painful red and purple rash in the exact shape of a handprint appeared on her lower back.

The girl eventually made it to another doctor, who treated her with steroids. The inflammation subsided, leaving patches of brown pigment that faded after a couple of months. But what caused the rash? It appears to have been the work of
mala mujer
, or “bad woman.” This desert-dwelling perennial has the toxic sap of a euphorbia and the tiny hypodermic needlelike hairs of a nettle. The victim had probably stumbled into a patch of it on her hike, and her boyfriend must have had remnants of it on his hand when he touched her back.

No one knows how the plant got its name, but perhaps those who had been stung by a wicked woman’s wrath recognized the sensation when they encountered
Cnidoscolus angustidens
—often described as one of the most painful plants in the Sonoran
Desert. This perennial shrub grows up to two feet tall and produces small, white flowers; it is easy to recognize because of the distinct white spots on the leaves in the fine hairs covering the entire plant. Although it is not a true nettle, it behaves like one: the fine hairs, or trichomes, easily penetrate the skin and release a tiny dose of their painful poison. One researcher found the pain from the
mala mujer
’s sting to be so excruciating that he called the trichomes “nuclear glass daggers.”

According to a 1971 newspaper account,
mala mujer
was rumored to be a treatment for infidelity in Mexico; husbands would brew a batch of it into a tea for their wives in order to control their sexual urges. But wives had a much more potent treatment for men who strayed: a hallucinogenic or possibly fatal tea made from the seeds of a datura.

Meet the Relatives
These other members of
Cnidoscolus
genus are sometimes mistakenly referred to as nettles: Texas bull nettle (
C. texanus
), found throughout the southern United States, and tread-softly (
C. stimulosus
), found in dry scrublands in the Southeast. Both can bring on nausea and stomach cramps, not to mention intolerable pain.