The flowers look like Campanula glomerata 'Superba', but I haven't seen such a big clump like that before, so I can't be certain.

It does look like a rather superb Campanula glomerata.My only doubt is that ours flourish in deep shade whilst this one is in full sun.

Its lovely, is it hardy?

Many thanks for the replies and I think Spritzhenry is right as I have looked at other pictures and they seem exactly the same. This one is in the shade until mid afternoon when the sun is on it for a few hours. I'm not sure if it is hardy as we only got it this year.

Thanks,

Will answer the supplemantary question, our is as tough as old boots. This is the first winter we have lost any of the millions of seedling which come up everywhere in our Crevice garden.

Thanks OB

Minus 15C last winter, Drc, its a nice plant and dead easy.

Well I hope I come across one BB

Watch out if you do, Denise - it can be a thug!

Oh!

Well - you don't get told things like that on plant labels, do you?

No you dont and with some such as Leylandii in the 70's it been a disaster for some.

Shudder......

If it is Campanula glomerata...watch out!....it will spread like mad.

All the campanulas grow like weeds here !