I trampled some Japanese knotweed in Palace Road Nature Garden this morning, that most famous of non-native invaders, introduced by the Victorians and capable of forming dense thickets that choke out all other forms of life. I wish I'd done it sooner, before it grew taller than me; I did try, but that was the day Scout got chased out of the park by a greyhound and I had to give chase through the streets.
I first saw the stems pushing up through the ground last spring, and wondered what could possibly be so vigorous. Soon they were lost in nettles and brambles, though, and it wasn't until this spring that I saw them again, and identified them. Soon, the government will begin releasing tiny bugs to combat it, the first use of 'bio-control agents' in the UK, but until then little can be done to halt its spread.
Fighting my way among the brambles I find that each stem gives up its hold on the ground easily, breaking sideways and bringing up a few small, harmless-looking roots; yet the impression is deceptive, as underground there will be a huge network of roots, a tiny fragment of which is capable of regenerating the entire thicket. So I am not going to be able to beat it, but perhaps I can slow it down.