Kalindi, I wrote a long answer to your question and lost it in a cyberspace black hole somewhere. LOL The last sentence was something about the border probably being a good idea; not just to keep the grass from spreading but to keep the border plants from spreading into the grass. As I was typing I was thinking of some of the plants that are advertized in the catalogs like Spring Hill Nursery. Some of the ground covers are flowering (like crown vetch), so you could vary the surrounding plants for color, height, etc. If you google "Ground Cover Plants" for your area you will come up with lots of suggestions; way more than I can make. Anne

Hi! I have a bunch of sedum, euphorbia, crassula as well as other succulent plants. Most of them are South African (zone 9). Take a look at these pictures and let me know if you are interested in any of these plants. Here is a link that might be useful: Garden Web Pictures

What a great idea for that space! You might want to peruse some sites to get a visual look at the plantings others have used (see my link below). Or just study creek beds (although your plants won't be the usual 'water' plants due to dry conditions (unless you want to lay a drip line along the banks of your stream). In real creek beds I think you'll find that there are all sizes of stones from boulders to gravel, grasses and wildflowers of different heights. It sounds like your choices will have to like a fair amount of shade. Also, I would recommend laying some thick landscape cloth in the 'creek bed' prior to adding the rocks. That way any weeds that eventually form between the rocks cannot establish very deep roots and can be more easily removed. Of course a little Roundup sprayed onto weeds might be just as easy. Here is a link that might be useful: google image pages of 'dry creek beds'

It doesn't seem optimum to plant something like ivy that would completely cover and smother the wall, and then move on and start covering nearby things, too. It would be better to plant something that would grow in the cracks but still let the rock faces show. You could plant it at the foreground, too, or plant something low and colorful there. But no one can make suggestions about what to plant unless they know where you live.