I can get you close :-) If it doesn't vine, then it is very likely one of the non-climbing herbaceous types. If a flat, open flower, I'd look at Durandii, Arabella, Harlow Carr, Wisely, or possibly Petit Faucon.

All herbaceous clems are considered group 3 or hard prune. You can pretty much take any of them back to ground level each year

Gardengal - Thanks for the list. Here is what I found. This clem vines but scrambles along the ground. It seems not be strong enough to hold onto a support or grow up. When I have tried to coax it up, it will either snap off or slide to the ground where it wants to be. Flower size is about like Jackmanii. The flowers on this plant are cornflower blue. From my Google searches, Durandii looks purple. Arabella is way too light. Harlow Carr looks blue at Dave's Garden and purple everywhere else. On Dave's, the blue color is right to my flower but HC says 8-10'. This plant is small. At 5 years it only reaches about 48".

Lets clarify some terminology :-) Clematis only "vines" if the leaf petioles wrap themselves around some sort of support - that is the climbing mechanism for this plant. If they don't vine, then they are considered herbaceous scramblers and are often used as groundcovers or to scramble through perennials or lower growing shrubs.

You want to be careful in interpreting colors from online photographs - they are seldom true to life and often influenced a lot by lighting. I grow (or grew) durandii, Arabella and Harlow Carr and all are blue - not purple - with Arabella being a paler sky blue, the others more of a deep indigo blue. And the size of any sort of clematis is extremely variable depending on growing conditions so I would not necessarily judge just based on that. My Harlow Carr never got close to 8-10 feet!!

If your plant does not vine as described but just scrambles, then it should be close to if not one of the blues listed. There are just not that many blue flat flowered herbaceous clematis varieties.

Blue and purple flower tones photograph less accurately than any other color IMO and sometimes the nurseries "enhance" a photo's color, and in my garden, light levels effect the color of blues, so photographing the same plant with the same camera at different times of day and sun conditions will give me quite different colors. So you want to look at leaf shape, blossom size and petal shape and gappiness/overlap, and the color and size/texture of the center boss of stamens. Sometimes petal count helps, though for many it's somewhat variable. Looking at the seed clusters may help.

If you aren't familiar with Clematis on the Web, you can fill in what you know (in this case that it's group integrifolia) and try blue, purple and violet for color to see what possibilities arise. However, GG48 has given you a good list of possibilities that are/were readily available in the US. Another one is Miranda, a sister to Arabella that is darker and was available for a while but seems to be no longer. If you aren't in the US, perhaps someone from your country can chime in. CotW is an international listing and not all are available in the US and not all are available on the market, so it will give you a lot of excess in the list of possibilities. There are a few in the River series developed by Wim Snoeijer in the Netherlands, but I don't know if any have been available in the US for more than 3 or 4 years, and I doubt if one would find them at a big box store.

Gardengal, That makes sense. Thanks for clarifying. I will try to get a pic if it comes back this year.

NHBabs - That is very true. Blues do not photograph true and I have seen some bad photoshopped pics. I will check out Clematis on the Web, too.

I am in PA zone 6. Sorry I forgot to mention that.