i have a vine plant growing wild and it is very prolific and has covered some trees. it seems to be trying to take over, much like kudzu in the south. i live in south central pa. this vine has a woody stem and a dark green and normally shiny oval shaped leaf. it has very crude "thorns" on the stem. the thorns are not very jagged but if you grab the vine and pull, they can get you. the vines like to twist around one another, giving low lying vines support for itself and an almost schrub-like appearance. as i said, it's growth is very prolific and has totally encased at least two trees. it is growing over some of my blackberry brambles and ticking me off.