British Columbia: ground cover clematis?

Hello,

Not sure if this is the correct forum but here goes...

I have a question regarding clematis which are sometimes referred to as "ground cover" clematis. I would like to find a clematis that could be planted at the top of a sloping 5 foot rock wall and allow it to spill down over the wall. The wall has a gradual slope so the plant could easily grow atop the rocks. I live in Vancouver and the rock wall gets a couple of hours sunlight daily. Do you think there is such a plant, as I know clematis like to climb upwards? Any thoughts or recommendations?

Thank you for your time.

 

Clematis jouiane 'Praecox' might work.

 

Sweet autumn clematis might also work. Ours certainly tumbles about.