Clematis can be used to good effect in that kind of setting, and come in enough shapes and colors to give you trouble deciding which ones you can't possibly live without :-)

OOOH, Clematis sounds good. Can I really train it to grow down rather than up?

How about annuals- Nasturtiums come to mind first- they cascade- at least the trailing ones do- Ivy- would Vinca Minor fill the bill? Maybe Black cap raspberries for an edible crop? Squash? Melon? Maybe a weeping pine? Um- I am reaching too far...
Julie

Yep, Julie, a weeping pine vine? Lol. It has been really hot. A nice cool drink and an air conditioned room would feel really nice about now.
But some annuals would probably look great. (Weeping Pine??)

Well, They do have weeping conifers... but what I was thinking was more along the likes of the ground hugging floppy trunked varities like a co-worker has in her yard. It doesn't bloom- but hers sure looks pretty with a yellowish- orangey tint to the evergreen foliage, and drapes wonderfully over her concrete retainer wall! Unfortunatly- she didn't plant it and there are no tags around it- so we don't know the name or variety....

If you went with an annal, there's Black-Eyed-Susan vines.

I just came back from the Arboretum and I saw a Dutchmans Pipe vine that was actually growing down! Well, it really grew up and over the trellis and was growing down the other side. It has nice leaves. I think I am going to research this vine a little more.

If you want it totally covered Va. Creeper, I think it is called. There are junipers too, if you want evergreen.

If you really want flowers and hiding power, clematis. Do a little research for what would work best for you. There are three pruning schedules and some of almost any size, there are those that climb and those that sprawl well and those that will actually do well climbing through shrubs or trees.
jan

If you want virginia creeper- please come take some of mine! I think it and the grape vines are trying to rid the back of the buckthorn- to no avail I might add.
You will see that it does have a lovely color in the fall- but you will have to work to keep it in check-
Julie

I already have LOTS of the creeper myself Julie. The retaining wall goes anywhere from 1 to 9 ft high. I really do want it all covered, preferably with something that I don't have to prune back to nothing every year. I might just come and get your grape vine though!

Your welcome to about as much as you can dig and haul away!
Julie