It helps some but can still break out. The best barrier I have seen are railroad ties set about half their depth in the ground because they are wide enough to where you can catch it quicker crawling over before it reaches the dirt. Might want to consider mixing a tank of round up and ground clear spraying it back every winter/early spring before other stuff starts growing, but just wet the leaves. Don't soak it because nearby trees/shrubs can uptake the groundclear I have seen it kill full grown trees when somebody went crazy soaking the area with groundclear.

Thanks for the advice and warning. I've been pulling by the roots which takes forever. I wouldn't spray RoundUp, but maybe whack the leaves off it with a string trimmer and brush the cut ends with straight RoundUp Concentrate for Poison Ivy and Brush. Some kind of barrier would be good, though, as I can never get it all and it will just creep back as I'm working somewhere else. Would it just grow under/over RR ties?

It is more likely to grow over than under them which is why I like them---they have to cover more territory to escape so it is easier to catch the buggers.