A 100% slope is actually 1:1 or a 45deg slope, but I have donned my rappelling gear and planted on vertical faces. Yes, the mulch will have to be replenished from time to time. I wish I could tell you how often but there are some variables. I also can't tell you costs because I don't know about either your plant or labor market. You can also get mulch for cheap or free from tree trimmers and some municipalities offer free composted mulch from green bins. You will also have to weed regardless, but the mulch makes it easier. Aggressive groundcover can itself become a weed, especially if it self sows. Plus, weeds are by their nature aggressive and can compete with a lot of aggressive groundcovers, at least for a little while. When I say shrubs, they can be groundcovers as well. They are just low growing shrubs. You can also mulch heavily (8-12") and sow perennial shrub seed. That is a proven restoration technique, although weeds will still come up. Since you are new to gardening, I will recommend this site, The Informed Gardener, especialy the bits about mulch.

I had the Sunshine Mimosa for a few years but took it out. It looked good in the summer but during the winter it was very sparse and the weeds would pop up between the runners. I put in some Alba Begonias in that area, time will tell if they do well. My neighbor and I planted some Baby Sun Rose ( Aptenia Cordifolia) in our swale where it was hard for grass to grow. It's spreading slowly but we like it so far. Perennial Peanut is another ground cover that you could use and you can mow it if necessary. I would remove the grass but then I always do things the hard way. Someone else might have a better suggestion for you.

Skybird, thanks I guess! You were very gentle. I did read the thread you linked. I've read others too where folks didn't seem to be having quite so much trouble. We live in the Greenhorn Valley (south of Pueblo)on a windy ridge. Our yard is all rocked with perennials, shrubs, trees, grasses. I dislike the rock intensely-- it's so unwelcoming, hard to walk on or work in, etc. -- but no mulch will stay down in the wind. What I hope to do is replace all the rock except the winding path with a groundcover. Any groundcover which can be walked on occasionally, is drought-tolerant, and not a attractant for deer would work. We have anacyclus daisies, which we enjoy, but it doesn't spread quickly. My husband doesn't want more woolly thyme, which we have in the back. We want some kind of a quiet background for our other plants. The look we were trying to go for when we started was a "foresty" look, but foxes dug up our irrigation lines-- never could figure out why really, but it happened night after night -- and only the rock seemed to stop them. I think groundcover would deter them also. I've attached a photo of part of our front yard from two years ago. The front doesn't face the mountain and ridge, but it still gets tremendous wind. I've looked online at groundcovers but this will be a huge project in terms of time, labor, and money, so I thought something like G.h. which I know will grow here and I like the look of would be best. I hear what you're saying, though. If you or anyone else has any further thoughts I'd sure appreciate hearing them, and thanks for taking the time to do such a lengthy and informative post.

I applaud your interest in using a practical groundcover for your hot, sunny area. This spring, I bought some rupturewort and planted it in a dry, sunny area. I'm watching to see how quickly it spreads. So far, it seems to be performing well in the 90-plus temperatures we've been having here in Fort Collins, CO. If it looks viable, I may use it as a lawn replacement. I've also been playing with Veronica pectinata because it's evergreen, has a beautiful green color and is drought-tolerant. It has been performing surprisingly well so far along the pavement at the edge of my front yard. Only thing is, after it blooms, it flops open for a while and looks ugly while it produces seed and recovers from blooming. But it's currently putting on more leaves and will look lovely again before long. So it's a question of whether you're willing to put up with a month or so of ugliness. Creeping thyme is quite attractive. It can, however, die out and turn brown in the middle, making it unsightly. Your mention of clover is intriguing. I researched it online. It appears that clover is quite drought-tolerant. But it's a short-lived perennial that needs to be reseeded every 2 or 3 years. A number of sources suggested combining it with grass. So if you wanted to experiment, you could seed Dutch white clover among your existing grass, you could see how it works out for you.