Looked all over the internet and found almost nothing on Dr. Ruppel, the hybridizer of this fabulous clematis. All I could find was "Argentina, 1973." Regardless. It's a lovely spring (and late summer) bloomer that popped open on my black fence this past week and caused spontaneous happiness among dog-walkers. This one came from the Morris Arboretum plant sale, which, if you haven't been to it, is one not to miss. It's May 12 this year (for the public).
At the local sales, plants are grown there by knowledgeable people who often are on site to answer your questions. That was my experience at Morris. I described the site - shady - and my desire for a spring rebloomer, and the mysterious 'Dr. Ruppel' was suggested. Good choice. It's got large (6-8") flowers with ruffled petals and a darker pink stripe down the middle. The color is described as pale "orchid purple" or fuschia, and it's billed as a good cut flower, though all I ever do with cut clematis is float them in a bowl of water.
'Dr. R' is a Group 2 clematis (a medal for you if you know and understand all this), which means you prune lightly in early spring or late winter. You can deadhead for reblooming or watch for the seed heads, which are supposed to be a show in their own right. Love this plant.