bur cucumber an annual believe

Definitely bur cucumber. I love them in the right spot - in a kind of wild area. They cover the tops of shrubby plants, with lovely little flowers. Definitely don't want them on my pine trees, where they tried to grow last year, but they seem pretty easy to remove.
I have read that they are invasive, I think it depends on the location. I have heavy clay, and particularly in an area that stays damp much of the year they grow, but only sporadically, so I let them be. This was the first year they came up into the pine trees on the edge of the yard, though, so I guess I'll find out how they behave in the dryer clay areas!