GTR-
I am an organic gardener, so would recommend the old dig and clear method. Herbicides like the organic Scythe and Burnout require 2-3 sprayings to kill the roots of the plants. You can also cut the vines back to the ground enough times to eventually kill the root systems by withholding leaf formation, thereby starving the roots.

Remember that trace amounts of herbicides is found in some composts that are made from herbicide-laden grass clippings. It does sometimes effect the growth of ornamentals. Too, you would not want to use this compost on your vegetable garden.

Some Washington State U compost was contaminated with picloram, a long-lasting herbicide used to kill thistle and other broadleaf weeds

Clopyralid is another culprit herbicide that has caused problems in the growth of vegetables even when the compost was over a year old. Here is a site from UPenn describing their difficulties with tainted compost.

http://www.jgpress.com/BCArticles/2001/070132.html

Basically, you'll do better grubbing the stuff out by hand and using the organic herbicides available today.

Ginger

Have you posted over on the Organic Gardening forum? They will probably have some good suggestions. If you DO dig--be certain to shower afterwards,in cool water, with Technu 9if you can find it) or Dawn for Dishes (if you can't find the technu.) Either will help you get the urushiol oil off your skin. (Dawn is what they washed the sea animals with after the Valdez spill--it's great for removing oils!)
Worst case of poison ivy I ever got was clearing an old stand of English Ivy by hand...NO visible PI--must've been roots...steroids for 10 days. NOT fun. Forwarned is forarmed!

melanie

Ginger and Melanie: Thanks for the great info on organic herbicides, soaps, tips and warning.

Didn't know about cutting back so much would starve the roots; I'm so glad to know that; I'll try it. I think that will be an especially good way to get rid of some honeysuckle that's interspersed in a hedge I don't want to lose.

Good point about remembering to shower. My worst case of PI was when I was pregnant; no steroids for me! My MIL swears by Fels Naptha soap for after dealing with brush and potential PI. ( I can't tell you how many times I've heard her exclaim, "Gina, get some Fels Naptha, F-E-L-S N-A-P-T-H-A and lather it up real good!" She's a professor and has a compulsive need to instruct, lol! ) Glad to know about the Dawn though, probably cheaper. I'll probably mostly dig; it's gratifying and great excercise.

Thanks again, G.

That picture looks very nice. You sure did a great job with that vine. I just bought a house where the yard has not been well maintained and have a trumpet vine. As I was doing some remodeling I was ripping out walls and found the vine growing in the walls of my house and crawlspace. This stuff is a nightmare for me. I have sprayed it and it sure doesn't like the stronger version of round up for ivy and woody plants. But it is everywhere and I have a long hard battle ahead of me. I want to just cut the thing down, but by neihbors love it and said they would kill for a trumpet vine. I just laugh, I would love to give it away, but I don't want to spread this nasty weed. Are there some other less invasive vines that I could grow in a full sun area.