The alien shrub that can't be stopped

The alien shrub that can't be stopped Alamy Japanese knotweed evolved in one of the harshest environments on Earth – now scientists are desperately trying to find a way to destroy it. "Scientists don't 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. As early as 1856, von Siebold & Company of Leiden's sales catalogue noted casually that that Japanese knotweed is "inextirpable" – a feature they apparently viewed as a benefit. But a liaison between this plant and the original mother variety could theoretically lead to Japanese knotweed that's male – i.e., it could make Europe's lonely female plant a mate.