My Rooguchi has a VERY long bloom season - longer than any of my others.

My longest bloomers are Ville de Lyon, Mikelite, and Gravetye Beauty. I choose plants partly on when they bloom, but mostly on a combination of their appearance and ease of growing since I'm not big on fussy plants. I've ended up with a few type 1 alpina and macropetala, a few large-flowered type 2s, and a bunch of type 3's ranging from large-flowered to viticella hybrids to various bells.

While this info sheet was written with a specific location in mind, it does provide a very helpful breakdown of what is expected to bloom when and the length of the bloom season. You may need to do some slight adjusting to fit your area/climate but the basic info is sound.
Clemson University clematis info sheet

Thanks for the info!