Rampant montbretia, any advice?

[HundredAcreOwl]

I've been lurking for a bit.

HI, I'm an unconfident occasional gardener, herbs mostly.

Any thoughts on how to get rid of or limit the montbretia would be very welcome. I've been told even black bags won't work, it'll just poke through. It's well over 25 years established.

Thank you.

I feel better now. I managed to kill some mint last year and I was thinking I was the only one...

If we’re sharing our gardening confessions, I’ve killed mint too. I used to plant it in bottomless pots sunk into the border, but the fancier varieties rarely survived the winter. I now plant it in wall pots, with far better outcomes.