Cherry Bells has darker flowers and foliage but this is C. punctata of some form. It may have seeded from your potted one.

Those leaves remind me of campanula 'Pink Octopus' which has pretty distinctive looking flowers. It's a spreader so I wouldn't be surprised to find it at a garden club sale.

Peren.all, the one in the photo I bought just this May. I see slight differences but so far have never been near it at the right time to see an open flower.

Sounds like I should not let this one loose in a garden bed. Do they spread by rhizomes or by seeding?

It spreads underground and by seed. The roots (especially of C B ) are like elastics and snap easily as you are trying to pull them up. I have Cherry Bells and Elizabeth that I am in the process of eradicating from the garden. Pity because the flowers put on a nice show. I would recommend not planting and save yourself the grief.

Thank you! I will be pulling it out. I wish I knew who brought this to the sale! I think I will mention it at future meetings. No invasives!

I have warned people for years never to buy from garden club sales unless they really know what they are doing. Far too many thugs are being sold to newbies.