I think that is Persian Campanula.
If it is, it is a perennial, not a biennial. Most Campanula that are perennial are winter dieback perennials that come back from their crowns. The best time to transplant them is in winter.
If you transplant it now, make sure you big clump of extra soil around it transplant.
Yours looks like a very nice variety with that shade of blue. I'm pretty sure there are now semi double varieties of Persian Campanula.
When I was a kid and first saw the word Campanula I pronounced it camp-uh- new-la. Course, that's not the way to say it. But at the greenhouse we liked to have fun with the Latin names, so that was what we called them when nobody was around.