Botanist John Wood explained in 1884, “After sending several baskets of plants to a friend, season after season, without satisfactory results… He was writing a gardening manual. A very unfortunate horticulturist can handle.
It is a Far Eastern import with red buds, beautiful heart-shaped foliage and gracefully curved stems.
In short, Wood has nothing bad to say about the plant, which, if you let it grow for a few years, will make a “beautiful rod” …
Of course, this is no ordinary bush: it is Japanese bitter grass (Fallopian japonica), with interesting details that Wood fails to mention.
Apart from its noble, perhaps slightly exaggerated, aesthetic qualities, it has a false good value, because if you have it, it is (almost) permanent: it will never die, and without drastic action, future generations will struggle against the dense forest of stems. .
Of the 13,000 exotic species that have traveled the world since the beginning of colonization in the 15th century, Knotweed The Japanese language is regarded as one of the most complex: it engulfs suburban gardens, swallows entire sections of railway tracks and floods canals and national parks.
Dan Eastwood, a professor of biological sciences at Swansea University in the UK, says that if this invasive shrub grows at will, it could quickly overwhelm the whole of England, except for patches shaded by trees. “There will be general dominance,” he says.
But the complete removal of these weeds is very difficult and mainly involves extracting the soil from it: digging at least five meters deep and removing the entire land almost radioactively.
If left alone, it returns many times, regenerating itself from small fragments and harming gardeners for up to 20 years after its apparent disappearance. One study found that just 0.3 grams, roughly the weight of a pinch of salt, can regrow from a root piece.
Unfortunately, you can’t put some herbicides in it. “Even if it looks dead it will grow back,” says Kevin Callaghan, director of London-based eradication firm Japanese Knotweed Specialists.
Aside from the fact that the ten-foot-tall weed isn’t ideal for monoculture gardens or wildlife. An infestation of this shrub can have disastrous financial consequences.
In the UK, the presence of a rod can instantly reduce the value of a house by 5% to 15% and many banks will reject a mortgage.
How did Japanese weed manage to become so incredibly tough? Will we ever figure out how to beat her?
An unwelcome gift
On August 9, 1850, a surprise package arrived in the mail at Kew Gardens Botanic Gardens in London.
The unexpected gift included several unusual plants and a note revealing the identity of the mysterious benefactor: Philipp Franz Balthasar von Sieboldt, a German physician and botanist.
Von Siebold had recently returned from the Japanese territory of Tejima, a trading post built on an artificial island off the coast of Nagasaki. During the Edo period of isolation, when it closed its borders to foreigners for more than two centuries, it was the country’s only point of contact with the outside world.
As a renowned physician, von Siebold had unprecedented access to contacts in Japan and used them to indulge his interest in plants: he had people collecting specimens from all over the country. But after a rare visit to the mainland and an unfortunate incident involving a banned map that local authorities found in his luggage, he was finally asked to leave.
So von Siebold packed up about 2,000 plants and headed back to Europe. This includes a wonderful shrub found in Asia, including Japan, Taiwan and South Korea, valued for its uses in traditional medicine and, interestingly, as a vegetable. When cooked, its fresh sprouts have a tart, crunchy flavor similar to rhubarb.
In short order, Van Sieboldt & Company of Leiden, a Netherlands-based company specializing in the sale of plants from the Far East, was born. And from the first moment, Fallopian japonica It was one of his star plants.
It was only natural that this vigorous beauty should be shared with others, and Kew Gardens received its own specimen. From there, his success was rapid.
Japanese weed was successful and within a few decades had sunk its roots deep into Oceania, North America and much of Europe. Many of these 19th-century clusters still exist today, in the same locations where they were planted.
According to Eastwood, this early fame was the first clue to his formidable hacking powers. “The truth is that it has been brought into this country and has been widely planted for a considerable period of time, since the Victorian era,” he says. “So, how many people are you talking about before they’re established in an ecosystem? [lá]Humans really played a big part in that.”
However, not all gardeners are eligible for credit. Bush is truly exceptional: a truly otherworldly alien invader. From the wasteland of volcanoes and poisonous gases. The plant’s natural habitat is the slopes of volcanoes, where it was one of the first to settle after the eruption.
It sinks its famously unstoppable roots into cold, solid volcanic rock and waits for years, even as the above-ground stems and leaves are buried in red-hot magma.
Away from this harsh environment, in the paradise of the average suburban garden, these natural adaptations are almost impossible for the plant to overcome. This story is the secret of its impressive expansion and survival.
“Every year, when photosynthesis starts, when the plant captures the light energy, it takes that resource and puts it underground,” says Eastwood. The surface parts wither and die each winter, but their rhizomes—a kind of twisted, modified stem—are still there, retaining the sugar they produce when they’re all good, and in the soil.
The following spring, the plant sends out new roots to expand its range laterally, and these produce more stems from the ground. In this way, it slowly advances until it monopolizes every available inch of space.
This two-part system, with body parts above and below ground, is very difficult to control with chemicals. The most effective is glyphosate, which works by blocking an enzyme that plants need to make amino acids. But the best way to use it is irony.
Many homeowners have discovered in their quest to eradicate it that overuse can lead to the plant accidentally spreading.
The part you see above the ground is the crown: this is the dominant part of the plant that actively stores energy. But he has support. “Around these crowns, there are dormant buds, so they can produce new growth, but they don’t because the crown suppresses them,” says Eastwood.
So, if you fill one of these weeds with herbicide, you can completely destroy the crown and suddenly all your satellite shoots are up.
A big mistake
Little did Von Sieboldt know when he sent the first specimen to London that he would become one of the greatest villains in the history of botany.
Unfortunately, Japanese weed isn’t the only invasive plant with a bright future to overwhelm vast swaths of the planet. In fact, two other major weeds currently of concern to landowners, governments and environmentalists share some startling similarities.
oh Heracleum montagecianum It arrived in England in 1819 after seeds were sent to Kew Gardens in the Caucasus Mountains in Russia. Today, its tall stems and white flowers can be found across Europe and North America, extending from highway shoulders, near railroad tracks and waterways.
In addition to being invasive, it’s highly toxic: it regularly makes headlines after unsuspecting people suffer severe blisters and chemical burns from its sap.
A Impatiens glandulifera Two decades later, a surgeon from India sent specimens to the Royal Horticultural Society in London. It quickly became a popular plant, prized for its delicate pink orchid-like flowers and dense foliage.
But within a few years it escaped into the wild, and by the turn of the century it was considered a weed.
Along with Japanese weeds and others, these plants lead to a botanical disaster, making it difficult to gradually replace native plants.
And the story is far from over. Although the elaborate gardens and uncontrolled plant imports of the 19th century are behind us, many plants found in millions of backyards around the world are believed to have invasive potential.
Eastwood is willing to bet that the next big invader will be the Japanese anemone. With pink, purple or white saucer-shaped flowers on slender stems, this member of the butterfly family is popular for adding color to gardens in late summer.
But like Japanese weed, it spreads easily underground and takes over quickly. People may not care too much about such a handsome invader; It is certainly difficult to imagine their presence reducing the value of a property. But if that happens… let’s say we asked here first.
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