I have the same problem with two....Mucuna sloanii and Thunbergia coccinea. I hate to have to ax them because both are relatively rare (especially the Thunbergia) but they are highly invasive here. I have been trying to eradicate the Thurbergia for over 10 years. If just one small piece is left rooted the whole thing grows back. I have tried to keep it contained on trellis but it doesn't work. It spreads by underground methods and pops up everywhere. Ditto the Mucuna.
I have been thinking about trying the really strong Horticultural vinegar. I have read you can get it in several different strengths.
