I generally use latex paint for doing paper mache for props and this is a perfect use for it. Get some foam pipe insulation and put it around some old/cheap garden hose then paper mache over the foam with some of those blue shop paper towels and latex paint. Just make sure to leave wrinkles for texture like you'd see with bark. The paint will remain a little flexible unlike traditional mache medium. When the vines are dry just paint them to look like wood and glue some leaves on and you've got some vines.
Bale wire run through flexible conduit and wrapped with masking tape for texture and wrinkles. Then wrap that with floral stem tape and seal it with a spray urethane. It takes a little time but looks good.
You can also use expanding foam for bark like and vine effects. There are some cool pics of that on the forum. I think they paper mache is the cheapest, but depending on where you live, might not be the best.