Yes,this violet (v. koreana) does bloom later in zone 6, and while its flowers are quite small in comparison to the common violets (v. sororia) that grow "wild" in our lawns, etc. they are charming nonetheless.

Another note: Most often, the "mother plant" does not return for me but I get quite a few volunteer seedlings instead. However,last year's largest plant has reappeared in the last ten days, along with a whole load of seedlings, which, when they get a bit bigger I will lift out and place where they can have more growing room. Don't worry, it is not invasive. Not all of the seedlings make it to maturity, and, like I said, it acts more like a tender perennial for me. I welcome the dozen or more seedlings that have appeared this year.