I am sorry for this delayed reply to your gardening question. We are transitioning to a new Q&A system and your question was unfortunately lost in the transition. I have discovered it now and hope this reply is not too late to be of help.
I'm not sure which plant you are referring to as potato vine as there are more than one that goes by that name. I suspect based on the difficulty in killing the things that it is Dioscorea bulbifera, sometimes called air potato.
While Air Potato is used as an ornamental in some parts of the south it is an invasive and difficult to control weed in your area. The Florida Extension Service suggest products containing triclopyr. The following web site offers more info. I also suggest you contact your County Extension Office for more info and control suggestions.
Thanks for the question. Please stop in again soon!
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