You definitely have a problem. The only thing that will completely stabilize your slope is clump forming grasses - they have roots that go at least 15 feet down, virtually everything else has surface roots. And many clumping grasses will tolerate clay soil and full sun. But they don't give a groomed garden look. They can look neat and tidy but that involves a lot of work on your part, and slopes are hard to work on. If this was my problem I would aim for a wildflower meadow look with plenty of tall grasses to try to keep things stable and I would add in the daylilies, black eyed susans and such to keep something blooming all summer long. I have seen slopes covered in Verbena so some people make that work. It always dies out after a few years in my yard. Some forms of it are amazingly winter hardy and pretty much bloom year round. I have seen slopes covered in blue rug junipers also. I love the easy maintenance but you have to remove every speck of grass or weeds because they can overpower the shrubs and weeding on a steep slope is difficult. Also, any shrub is going to need a lot of watering to get it established and if this summer is a dry one, that will be hard to do. If the clay is holding up and not washing downhill you may not need to worry about erosion control at first. It all depends on just how steep your slope is. If you live in a neighborhood where a wildflower meadow out front won't go over well you could choose one type of plant and cover the entire slope with it. That mass of uniformity will look managed and planned and hopefully solve your problem and depending on what you grow could be virtually maintenance free.

Hello, I have the problem that I need some kind of ground cover for the ugly slope in our backyard. Since it is clay (and I mean nothing but hard dry clay) I know that not a lot of things will grow there. I am trying creeping phlox right now but I know that it is unlikely to make it. But it gives you a general idea what I am looking for. Could somebody recommend a FAST growing ground cover that is at least somewhat pretty (colorful) and grows here in hot South Carolina in clay?

My Mother used candy tuft not sure if that is the same thing but it worked well and had a beautiful small bloom on it

I'm putting in some liriope now, so I'll toss that idea in. It's a great bank cover too. A combo of a few clumps of 3-4-foot high junipers at the top, **chosen for their handsome form**, and Liriope spicata or muscari spreading around them and across the bottom would tame that bank nicely. (Throw in a small tree, like a crape myrtle, to screen the house beyond from view?) In any case, spicata spreads by runners to form a very dense cover. Muscari is clumping and would also do well, without requiring you to install an edging to keep it from moving into the lawn, but it would require more plants and take longer to cover completely. Both are very tough, come in solid and variegated forms, and, notably, would both take those dry top-of-bank conditions mentioned in Killerv's link and the likely much moister conditions at the bottom.