It is apparently hard to kill. Deep resilient spreading roots, leaves that don't absorb water, tolerant of many soils and sunlight. I even have some I put a trash barrel over last summer; the entire vine is white but won't die. They are surviving by nutrient spread from uncovered vines.
I weed-whacked them last week. That should weaken them for a while. But it seems there are only a few ways to eliminate them. Digging the roots out 2' down, covering them in black plastic for a couple years, and using herbicides.
Digging down that far needs heavy equipment and the space is too tight. I can't cover them all with plastic as they are among plants I want to keep. So that means herbicide. And it means an oil-based herbicide.
I try to stay organic. Not certified, but in general practice. So in the open areas it has invaded, I will spray carefully. I have a large cardboard box I have cut the bottom out of and made a small hole in the top. I will spray Triclopyr into the hole, let the box sit sit 5 minutes and move it to the next spot (wearing latex gloves and a mask).
Then I will cover the area with black plastic (I have large rolls of the stuff). For the individual plants in the flower beds, I will apply it with a 1" brush on leaves. And since I'm going that far, I will use the box on the poison ivy and the english ivy ("in for a penny, in for a pound").
