How to kill pyrostegia venusta
Hi folks. We have a pyrostegia venusta vine that we want to get rid of. We've cut it down to ground level, but it's developed great thick subterranean roots that have spread along an area near a dividing fence of about 8 metres. I have no idea how far they go down, but it looks like a hell of a job to dig them up.
The bits that are still above ground keep sprouting new growth, which I keep cutting off. I have searched on the web, and it seems Garlon is the herbicide that will do the job, but it sounds like nasty stuff. I don't even know if it's publicly available here.
Does anyone have any tried and true tips on how to kill this thing, please? If I have to use herbicides, I will. Just wanted to see what recommendations might be out there.