The alien shrub that can’t be stopped – Japanese knotweed
Out of the 13,000 alien species that have made their way around the world since colonialism began in the 15th Century, Japanese knotweed is widely regarded to be among the most intractable – smothering suburban gardens, swallowing up whole swathes of railway line, swamping canals, and creeping into national parks with its searching tendrils.
By Zaria Gorvett
BBC
6th October 2022
Excerpt:
Unfortunately, you can’t just throw some weedkiller on it either. “It could grow back even though it may appear dead,” says Kevin Callaghan, the director at Japanese Knotweed Specialists, an eradication company based in London.
“Scientists don’t [usually] say never,” says Eastwood, but he is willing to take a bold position and say that you never end up killing off an established clump of Japanese knotweed permanently this way – it’s literally impossible with the chemicals that are legal. “You’ve got to admire the plant really,” he says.
Aside from the fact that a monoculture of 3m (9.8ft) high weeds isn’t everyone’s idea of the perfect garden – and it’s not exactly ideal for wildlife – Japanese knotweed infestation can have catastrophic financial consequences too.
Each spring, as its asparagus-like tips not-so-tentatively push their way up through the soil, thousands of landowners across the globe turn as green as its foliage – knowing that they might as well have chopped up tens of thousands of pounds and used them as fertiliser.
In the UK, the presence of just a single stem can instantly knock around 5-15% off the value of a house, and lead many banks to refuse a mortgage. The plant has even been known to render properties entirely worthless.
