I saw it two years ago lying on the floor in a broken open pot at a Home Depot, roots out. it looked healthy, had a couple of flowers, and I thought It would be dead by tomorrow. So I bought it and planted the same day. The clematis proved to be grateful, took off right away. I would like to know what it is, as it looks like it might use some pruning later on.

It is a vigorous plant, growing fast, looks somewhat similar to Lasurstern but the flowers are a bit smaller (still big enough) and, I think, the leaves are smaller, too. I believe it's blooming on the old wood (I might be wrong, as I am still a newbie).

Thank you for your help!