I can't really say since I don't grow Jackmanii and my Polish Spirit is new, but I will say that I bought it because someone here said it bloomed its head off for her. I'm hoping for good things.

I would choose Polish Spirit because Jackmanni is the more common one around here. I like having something different. That said, my second clematis was Jackmanni because that was all I could find. Happily nowadays the nurseries in the area and the big box stores carry many varieties. Polish Spirit just opened today and it is lovely, such a deep purple and nice sized. I now have about 90 different clematis plants growing in my gardens or waiting in my holding bed for a trellis and a permanent location.

My Polish Spirit is about 5 years old, is fabulous, a blooming machine, love it. Have 100 + clems and have never bought Jackmanii for the same reason mngal stated....it's the common one everybody has. Just planted two yesterday with 10 more waiting on the deck. MN gal....think we are on the same wave-length!!!
Guess that's why I have over 200 varieties of hosta but not "the green & white one." Marlene

Have about 30 or so clems of various kinds in my St. Paul MN garden, including Polish Spirit and Jackmanii. I love them both, but were I to be limited to a single clematis if would doubtless be the venerable--and perhaps overused--Jackman (not Jackman superba, which in its transformation seems to have lost the amazing glistening purple of the original).

Just my $.02, of course.

Gary

This post was edited by garystpaul on Wed, Jul 3, 13 at 18:02

I had my Jackmani for 33 years now and, (since I learned the proper pruning recently) is just one massive mass of purple. I added a Polish Spirit last year, and it has grown amazingly well and large but has not bloomed as yet so I will keep you posted.