You sure its Campanula? Only its really easy to dig out...

Can you post a photo?

Sounds like you might have chosen the wrong name for the plant that's giving you trouble. Campanula doesn't sound right.

Would love to see a picture! :)))

Campanula Elisabeth nearly ruined mine ...the white spreading shoots became entangled in just about everything and it spread like a weed.

Is this the 'rockery' type of Campanula? You could try weedkiller on it!

Mine was a Campanula Takesimana variety,incredibly pretty and two foot tall listed as a "clumper" but those white runners crept in to every plant in my bed despite me digging up the original plant after a year when I saw how much it was spreading .I had to lose some lovely astrantias and geraniums as the dreaded Lizzy overtook them.

Even so, Susiespearin, Soosiegray's comment that 'nothing seems to work' implies that weedkillers have been tried (and for all I know, a flamethrower and/or napalm) but the plant is untouched. Not something that would be true of any Campanula.

No, true, weedkiller would work on that .

I have two Campanulas I'd describe as 'invasive', although I can control them. One is 'Pink Octopus' and the other is C. Poscharskyana...errr....I think that spelling went a bit wrong!