Clematis: I've got clem blooms (beginner's glee!!!), 1 by HBJoe

HBJoe wrote:
Hi folks ! Last week a friend and I were exploring a brand new trail opened up for hikers, bikers and horses in South central Virginia (7b). We hiked for approximately 6 miles and observed along the pathway some very delicate, blue flowers growing on both sides of the trail. I did not have a key, but suspected that they might belong to a Clematis genus.

My main interest is flowers that attract hummingbirds along the migration route. I just published a new book HUMMINGBIRDS AND FLOWERS THEY LOVE. I am grateful that it has earned an Audubon endorsement, however I anticipate that I will be embarrassed sooner or later by having left out a few flowers. I did not see any pollinators visiting these except a few bumblebees. Hummers ignored them. The flowers were growing close to the ground and supported by a long network of vines. Can one of you Clem gurus come to my aid and identify this sucker?