Found it growing in the middle of some other vines on a long stretch
of fence. The vine came up this summer sometime and the base of the
plant is already about 3/4 of an inch in diameter. Dunno if I should
leave it, move it or get rid of it.

http://www.vespertinal.com/junk/vine.jpg

http://www.vespertinal.com/junk/vinebloom.jpg