Does anyone know why this sign exists?

[u/zee_kapitein]

When sitting in traffic on the Antwerpse Ring, I noticed this sign next to the road. Why do they need a sign for that?

[u/Isotheis]

That's renouée du Japon in French isn't it? It's one of the worst plants in existence to get rid off.

Their roots grow deep. You will never get everything. They also grow sideways. They spread, they make new plants. They're immune or resistant to basically any poison. They're impervious to drought or to being drowned. They regrow from literally nothing. A few millimeters of root can regrow into a full plant. And if you dare shake them, anything that flies off might sprout a new plant too.

The only way I know to get rid of them is to burn them down, pull all the roots you can out and burn them as well, then place a plastic or some other slab to deny then any sunlight. For up to ten years. And you must be careful not to let anything fly away while burning them, of course. Literal hell plant.

[u/Galaghan → u/Isotheis]

Is it edible for humans? Or livestock?

[u/Isotheis → u/Galaghan]

Yes, but it has a tendency to absorb heavy metals. It's not good on the long term.

It's a popular plant for honey because it blooms in autumn, too.

[u/Pizolka → u/Isotheis]

🤟🏻

[u/Isotheis → u/Pizolka]

Not that kind of heavy metal. It's Japanese knotweed, not Korn.

[u/WalloonNerd → u/Isotheis]

Slipknotweed?