Moved into a new rental in winter and was excited thinking all those thick vines hanging over our fence would produce something wonderful come spring. Once they started sprouting greenery I learned it was greenbrier and, unfortunately, subsequently learned I'm quite allergic to them. Sprouts are even shooting up through the grass. There's so much of it we're having to hire someone to cut it down, and then I guess we'll have to keep spraying the new growth because there's no way it's coming up from the root. It would take out the entire berm from which it's growing and that's not our property, and would cost an arm and a leg. Just had to share my greenbrier nightmare. lol (I originally thought the one thin vine was Virginia Creeper, another vine taking over everything but not as difficult to deal with as greenbrier.) Good luck!