An invasive Japanese plant that can grow up to 15 feet tall is now taking over yards across the U.S. and threatens to dramatically reduce home values in the Northwest, Midwest and Northeast.
Japanese knotweed is a beautiful plant with beautiful white flowers and bright green leaves. You often see it along roads and in backyards.
But in reality, the plant, which resembles bamboo, has the ability to crack pavement, kill surrounding species and drive down house prices, the Wall Street Journal.
The species can grow at a rate of one meter per week and it takes years and a lot of work to eradicate the species from properties, even if the stems are injected with pesticides.
“You have to respect this plant,” Robert Naczi, curator of the New York Botanical Garden, told the WSJ. “They grow inches a day in the spring.”
Japanese knotweed (pictured) can grow to nearly 15 feet tall at a rate of three feet per week and it takes years and a lot of work to remove the plant from someone’s property.
To the eye, Japanese knotweed is a beautiful plant with lovely white flowers and bright green leaves that can be seen along roads and in backyards
Caitlin and Paul Maher Jr. of Lubec, Maine, had no idea that the 8-foot-tall plant growing on the land of their newly purchased home in 2020 was Japanese knotweed, or how much of a hassle it would be for Paul to get rid of it.
“It was a Vietnamese jungle. I couldn’t even walk through it. It was impenetrable,” he told the WSJ.
After years of mowing the plant, burning the stems, leveling the ground and scything it, which left him with a torn shoulder blade, most of it is gone, but he still cannot say that he has won the victory.
Every now and then small pieces of the plant come up that he has to treat.
He compares the emerging weed to a survivor of a nuclear war.
The plant, which resembles bamboo, has the ability to crack pavement, kill surrounding species and drive down house prices.
“I don’t think it’s a coincidence,” he said.
‘I call it plant consciousness.’
To remove a small portion of the plant, Cornell University professor Dr. Bernd Blossey recommends mowing the plant regularly to keep it under control. You can also dig it up to get rid of it completely.
However, digging it out does pose some challenges, as you have to remove the entire root to prevent it from growing back.
And it will take years for it to disappear completely, because it has to be dug up again and again.
The plant has also spread throughout the US (pictured) in the Northeast, Midwest, and Northwest
Another method is to cut the plant after it flowers and inject the stems with a weed killer, using a tool that looks like “a little gun with a syringe on it,” Blossey says.
If a victim of Japanese knotweed does not destroy the plant, the weed can spread unchecked, disrupting ecosystems and forming dense thickets that can be harmful to local wildlife, according to CNY News.
The plant has now become one of the most invasive and harmful plants in the UK, and homeowners must report if they have it and can take out insurance to protect themselves against it.
Until recently, some British banks would not give mortgages on a house if the factory was on the site.
“You have to respect this plant,” Robert Naczi, curator of the New York Botanical Garden, told the WSJ. “They grow inches a day in the spring.”
It can turn different colors as it grows and can take years to completely disappear.
According to the WSJ, residents who have the plant on their property are advised to purchase five to 10 years of insurance to cover the weed’s treatment and maintenance.
In the US, the University of Massachusetts Amherst Division of Environmental Protection released a bug called Aphalara itadori in 2020 after obtaining permission to do so.
It is the Japanese knotweed’s worst enemy. Scientists have placed them on individual giant knotweed plants and put nets around them to make sure they do their job.
“I’ve never been so excited to see a plant suffer,” Jeremy Andersen, a research assistant professor at the university, told the WSJ. “They looked like the life force had been sucked out of them.”
Since then, the species has spread throughout the US, particularly favoring wetlands with disturbed soil, such as near roads.
While the insects don’t do as well on Japanese knotweed, scientists are testing a new insect from a colder part of Japan that they hope will be better adapted to the Massachusetts climate, Andersen said.
According to WSJ, the plant was first introduced to the U.S. from Japan in the mid-1800s by botanists who also brought kudzu and oriental bittersweet.
According to CNY News, the disease has now spread throughout the US and is particularly fond of wetlands with disturbed soil, such as near roads.