This is a detail from the top of the piece, and I'm happy to say that there is no dirt or damage after the clematis grew on it for six months, and also none from the weight of it. Phew!
The bottom part of the fabric is loose enough so it can blow in the wind. These two pictures are diagonal views (front and back) as the wind is blowing it. I honestly don't remember if I purposely left it loose or if it stretched a little. I'll have to check older pictures. Either way, it has no problem standing up to high winds, which we also had yesterday.