It's a native vine so not sure I'd consider it a weed necessarily :-)) Only if it is growing where you do not want it.

It is one of the many bell-shaped clematis species native to the Southeast. I'm leaning towards C. glaucophylla with that very rounded leaf shape, possibly C. pitcheri, but I am not nearly as familiar with these less common native species as I am with the more commercial varieties. Colors on these are pretty variable with the literature showing darkish purple-red flowers all the way to a lavender so pale it looks like white, like the above.

I honestly don't think it is a clematis, though the flowers look a bit like some of the viorna group clematis. The leaves aren't compound and don't grow out of the stem in the the way I expect clematis to, and while clematis stems may be angled, they aren't square. Also, the bell Clematis don't have separate sepals at the base of the flower.

I'm afraid NHBabs is correct. We eliminated the Clematis varieties on various points. The leaves on this vine are actually slightly hairy and that stem is distinctive. It also never achieves a 'woody' status which the clematis do as the vine hardens off with age. Most of these flower pedicels don't ascend like Clematis ( I REALLY wanted to make it become a Clematis :) ) either, so I had to give it up as a bad job.

Can you give us a little more info on the location?

Certainly - the vine is in South Carolina zone 8a. Though it does seem to be able to handle full sun it also does quite well in some shade. There is considerable agriculture in the area (rural - very rural.)

Thanks - that is useful. I am surprised no one has identified it yet because it is so distinctive. But I can't even pin down the family.

Salpichroa origanifolia?

There is a new app called Grow It that you can ask people to identify plants.

nonmember_gw, you are AWESOME!!! That's it! Like floral_uk, I couldn't pin down much of anything - I had actually noticed some resemblance to Lily of the Valley, but that was all I got on that front.

So, Salpichroa organifolia or 'Lily of the Valley Vine' it is. Thank you to you all for helping to end a looong search. :)

Emily Saba, I'll check out Grow It and thanks - never can have too many resources.

Good grief - I would never have guessed Solanaceae.

Nor I - just amazed.

I thought it looked like something Solanaceae, mostly because of the leaves and sepal shape, but hadn't found anything that resembled it when I tried to look it up. Nice to know what it is!

The flower bud looks just like a physalis but I could t find it when I searched for that... Just looked and its synonymous with a physalis! Thanks nonmember.