I bought both at the same time two years ago and the verdict is J. Superba is the better plant. More vines and more blooms.

I read in one of the clematis books that the author felt that J. Superba was the better plant as well.

"New" is relative.........'Jackmanii Superba' has been around nearly as long as 'Jackmanii' :-) Over 100 years anyway! And there is some confusion among clematis authorities if jackmanii exists at all any longer as a true hybrid cultivar. The consensus is that most plants sold as jackmanii today are really Jackmanii Superba.

Here is a link that might be useful: A 'true ' jackmanii??

Thanks to both of you - that attachment was also really helpful. I'm going back to get Superba and grow both. I did feel that the blooms looked different - Superba's looked bigger and were shaped differently.

Westy

I'd like to bump up this thread. I have had the regular Jackmanii many years and bought a Jackamanii Superba just a few years ago. So far my regular Jackmanni seems much more of a blue purple compared to the Superba, which seems a more red purple.. But, as Superba is a younger plant and the blooms have not softened with age yet, it could go more blue. Anyone else have observations to share?

I agree with you, Superba seems to have more red in it and therefore is more purple and less blue. I prefer the bluer x Jackmanii, and also like that most of its flower have only four sepals - would others agree that Superba tends to have more flowers with five or six? I think the cross pattern the four-sepalled x Jackmanii makes is lovely in its simplicity and rather distinctive. Having said that, I’m here because I could never be sure if these differences I perceive between the two forms are constant.