it’s time to play ‘name that vine’
The plant in question, an East Asian native, is Codonopsis lanceolata (and don’t ask me how I even remember such trivia, when more days than not I can’t remember what tool I was going to get by the time I stand up to walk toward the barn). C. lanceolata, the bonnet bellflower is (no surprise) a Campanula relative.
Though virtually nobody in these parts grows it, you can: Asiatica Nursery sold it, and Digging Dog has its blue-flowered cousin, C. clematidea. As the species name of the latter seems to imply, grow Codonopsis like Clematis: up and over trellises or shrubbery, where their feet will be in shade and their heads in the sun.
One person who definitely does grow them, and in a big way, is Paul Kneebone in England, who has created a whole website in their honor. Other enthusiasts include growers who produce the ingredients for traditional Chinese medicine, since C. lanceolata is apparently also known as “poor man’s ginseng,” and its roots used in similar ways, though it is much milder.
Decide you don’t like it after all? Dig it up, then season and broil the roots Korean-style according to the recipe on this page (which also tells the medicinal uses).