Q: English ivy is taking over my back yard. It has probably been there for twenty-plus years. What’s the best product to kill it?
A: I’ve used glyphosate (KleenUp, Roundup, etc) and triclopyr (Brush B Gon, etc) very successfully to kill ivy. In my experience, you have to be patient. You won’t see damage to the vine for a couple of weeks. I spray every three weeks to keep a three-foot wide ivy-free zone around my fence line.
If you have a large, flat area of ivy, mow it first, as low as you dare go with the mower blade, then spray the sprouts when they emerge in a few weeks.