this is how it pops out of the ground. I'd say this is how it begins, but i really think it has traveled all the way over underground from the other side of the fence because when i pull up the weeds it just keeps coming and coming all the way the length of the yard.

Here is a link that might be useful:

Almost looks like it could be wild strawberry,

it does not have fruit and it grows very tall. Leaves are smooth and redish when they first pop up. Jagged edges on the leaves.

Looks like a type of blackberry vine. Blackberries fruit on second year growth, so if you're cutting them back, that is the reason you're not seeing fruit. They are pretty hard to get rid of, especially if they're originating on your neighbor's property and nothing is being done to contain them. A barrier sunk into the ground may keep it from invading the area where you plant your hydrangea. Constant cutting to the ground or mowing will eventually kill it, or spraying with Round-up in the fall, when it will be best translocated to the roots.

Here is a link that might be useful: blackberry control

BINGO! I think you got it. Blackberries are prominent in North Carolina and this is the first year I've seen flowers on this. Thank you for the advice!