Chris Lewis wrote:

According to Fred :
I've heard lots of horror stories on the home owner destroying
valuable landscape when spraying for poison ivy (or any weed using
weed killer).

With a pinpoint sprayer and no cross-breeze, roundup is pretty
selective.

....

Roundup is not selective at all...what you're describing is applying
it only to the undesired foliage. 2,4-D or other broadleaf herbicides
are both selective and effective on poison ivy.