Plants that became pests

I planted mint in a border.

The other pests were already here (Spanish bluebells, a massive pampas grass, Japanese anemones).
Our kerria is big but it's in a place where it would be awkward to grow anything else.

 

Cucumbers.

An innocent cucurbitae growing in a boggy corner minding it's own business..

Then some fool decides to take it into cultivation

It now infests every tuna and salmon sandwich in every supermarket throughout the land

It's even developed a survival strategy of getting itself finely chopped so you can't just take it out of the sandwich and hurl it at the nearest poor unsuspecting seagull

 

We know your culinary tastes don't run to cu's Zigs but have you thought of making your own sarnies.

When I was in my teens I would quite happily eat a whole cucumber on it's own regularly.

 

I did, the cucumber still got into them, it's incredibly invasive

 

You'll have to spray it with glyphosate @Zigs, that'll work. Don't eat the sarnies after though!