permaculture

[Jack Rowe <jackrowe@compuserve.com>]

More seriously, though,

9% vinegar sprayed on poison ivy leaves will kill them (especially in
sunlight and warm weather)... they will come back from the roots, and must
be repeatedly sprayed. If successive sprayings are made while re-sprouted
leaves are still small, the roots will starve in a season (if leaves get
very large, the roots recover quickly and the spraying can go on
indefinitely).

I've heard Steve's goat suggestion works very well. 

Only moderately sensitive to poison ivy, I far prefer it to Roundup...
having said which: 

Roundup sprayed full strength kills leaves too quickly to be well absorbed
into roots... tests have shown that three successive 1/3-strength sprayings
work better at killing roots, because the leaves stay on and continue
passing enough toxin to the roots to kill them. Please don't ever purchase
Roundup. Find someone with a supply of Roundup who is credibly and forever
forswearing the stuff, and use the last of theirs. 

And remember the ditty: Red and yellow, deadly fellow... leaves of three,
let it be... or something...

Jack