I think round up would eventually kill it. As is, there is still life in the roots.

I have four wisterias that I thought, I had managed to kill with round up. But, on two of them are new shoots coming up from roots, a few feet from the original plant. I will have to spray again.

Moni

Thanks, Moni, maybe there's hope...

Yes, make a fresh cut so the Roundup gets taken up.

Is it possible to cover and wrap the area in plastic to block out the sunlight, therefore letting it die naturally?