Sure I prune, Brenda, but only the tendrils as they grow. They are rapid growers, you can almost see them reaching out for the next thing in their path. So I prune, but it isn't exactly pruning. They are horizontal growers, so luckily I don't have to climb ladders to get to the top. But I cut the vines just like any other vining plant. They don't branch, unless you prune them back to the woody stem.
You might have ground runners too, but those are wound around the trunks to help add more support.
If I were you, I'd get some good soil, crack or cut away the container of the one you think is in the ground, then add the soil in a little mound and just let it grow. It will need a stake of some sort, though.
