This is the Guardian. There's a science fiction novel from the 1950s called The Day of the Trifids.

It's about an aggressive species of carnivorous plant which takes over the world.

You might not think a plant could be that terrifying in real life, but there's one species

that strikes fear into anyone looking to buy somewhere to live.

Japanese knotweed.

This once admired ornamental plant is so hard to kill and grow so rampantly

that homeowners can face being sued if they don't declare its presence when they sell a property. But how did Japanese

not weed end up in the UK? Why is it so damaging? And what might our attempts to get rid of it be doing to the environment.

From the Guardian I'm Madeline Finley and this is Science Weekly. Saman Subramanian, you're an author and journalist, and you recently wrote a long read for The

Guardian called The War on Japanese Notweed. Now that might sound quite extreme for a plant.

So tell me, what is it about this knotweed that makes it worth inciting a war over.

Well, the first thing to say about not weed is that it looks like a relatively harmless

plant.

It was imported into the UK in the 1800s in the mid 1800s and it was actually used as an ornamental fixture and a lot of British gardens.

It puts out these lovely little creamy flowers late in autumn and otherwise has these big heart-shaped

leaves and really a knotweed stand in a garden by itself.

It's quite nice to look at it. It's a pretty big plant. But in that

harmlessness is also hidden a kind of ineradicability or well not read is indestructible almost and I think that is really

the source of a lot of fear and anxiety that people have with not read which is that once you found a stand or a colony of

not weed it becomes very difficult to remove it and it therefore just grows underground and overground until it takes over an entire patch of land.

This doesn't always happen, mind you, but it can happen, the chances are good.

And so the question of what happens to a garden

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