On 28 Jul 2015, "(PeteCresswell)" wrote in
alt.home.repair:

Bottom Line: Should Roundup be effective against poison ivy?

I had rampant poison ivy in my yard when I bought the house. I
physically pulled most of it out and treated the rest with a brush
killer (it might have been a Roundup brand product.) I seem to recall
trying regular Roundup but it wasn't very effective. The brush killer
worked very quickly, like within a day.

P.S. - I haven't seen any more poison ivy back there for many years.
However, I saw a couple of sprigs poking up this summer. I killed them,
but it reminds me that the stuff may never totally go away.