Here's Zephirine Drouhin from Mastering Horticulture.

If your wall isn't light colored you could use white.
Multi Blue may be nice. Or Tie Dye. I'm wondering if Nellie would get lost.

My first thought is rooguchi, if you like bell shaped flowers. It blooms from may to september in my zone and it grows very fast.

Multi-blue would also look very nice. I'd go with a purple clematis if it were me. Good luck! I'm sure you'll find something wonderful to go with ZD. It's such a gorgeous rose! :o)

Michaela

If it's on a north wall, do you mean a north-facing wall or one on the north side of your property and therefore south-facing? Assuming north-facing, most clematis need at least 5 hours of sun to bloom well, so I am not sure that this would be the best site for a clematis, though you can do a search for shade tolerant clematis. If you can find a spot with half day sun, ZD will bloom better (it's shade tolerant, but will be healthier and bloom better with some sun) and any clematis you pair her with will also bloom better.

In my garden, Daniel Deronda does rebloom some after the first large flush.

There aren't many scented clematis, and the two most common, sweet autumn and Betty Corning, are both too large for ZD. Brushwood Nursery has a couple of scented clematis in the blue range (Sugar-sweet Lilac and Sugar-sweet Blue) that are in the right size range, but mine are first year and so I can't give any feedback yet.

Other than that, be aware that some years ZD will die back to the ground in the winter due to cold IME, and look for the clematis you choose to be of a size to not overwhelm ZD.

Thanks all! I'll post pix of the first flowers, once I can make up my mind :)