I adore the vine Mina lobata, also known as exotic love or spanish flags- i think they would add lovely color. also maybe some ivy would go well if you like the all green look.

-arielle

Thanks arielletea -

I looked that up and it looks beautiful, though it's an annual vine. I'm not very good with annuals - spring is my busy season at work so the time for planting seems to pass me by.

I was thinking of something perennial and evergreen if possible. Looks like we may have to go with Boston Ivy unless we can come up with a better idea. I've been warned against Virginia Creeper and Sweet Autumn Clematis -I guess they get out of control. It seems like Boston Ivy might also. Does anyone have any other ideas?

Hi,
I know you're looking for a vine but have considered growing moss on
your walls. From what I got your walls don't get much sunshine, if that's the case
Why not give it a try.
If the idea is too novel , why not plant trailing/ rambling plants. Like hardy geraniums?

Here is a link that might be useful: Moss Walls.