It looks like Campanula glomerata/Clustered Bellflower. Not sure of the variety but maybe 'Purple Pixie'? Marg

Yes I think it is clustered bell flower as well. Mine spread a lot and I keep ripping them out. Pretty but I wouldn't put them in a bed where you want things to be nice and neat. Well at least I wouldn't.

Thanks so much for your answers. That's exactly what it is. I did an image search on "clustered bellflower" and bingo. I too thought it was some type of bellflower but I had never seen them clustered.

Thanks again.