Old Wisteria

The house I just moved to has three wisteria "trees" (twined up and around big poles). One of the my FIL hacked up without my permission.
I'm thinking of leaving just one. They shade areas I really want to do vegetable gardening. They are also very invasive.
They seem so dead though. I very little green growth. I don't see how they could still be alive.
My neighbors said one of them (the one I might keep) flowers in the summer.
Is it possible to transplant wisteria? It's growing up and around a fence, I would have to hack it to a foot or two above the ground, and then dig it up. Would it survive this?
Am i going to regret killing them? I hear they take 15 years to flower from seed.

Wisterias are very hardy in general. Digging them up isn't likely going to kill it. There are different kind of Wisteria, if it flowers before the leaves unfurl, you've got Japanese Wisteria, if it flower after the leave unfurls, it's Chinese variety. Then if it blooms later in the season, and keeps on blooming into the Falls, it's American Wisteria. They also grow very rapidly from cuttings, and produces flowers sooner versus grow from seeds. So move them about, train them to the form you like, and enjoy them. It takes work to keep them from spreading all over the places should you grow them in the ground. I successfully grown some in half wishkey barrels.