My Nelly Mosser Clematis was planted when we came to live in this house in 1981 and has flowered ever year since then , some years better than others , This year bountiful in blossom after a rather severe pruning last year !
Nelly is a very prolific bloomer. Mine seems to be quite a bit paler than yours, judging by our respective photos of them. Wonder if, like hydrangeas their colour is affected by the soil.