There are all manner of things that will grow wwell there....but first you will need to get rid of the weed cloth and the rock.
If you don't want to do that....there is not much that will grow there....because without the decomposition of mulch and things that fall and the interaction between soil surface and the atmosphere....that area will always be heavy clay....
Linda C

Hi Yebba,

You have a big enough area to put in a wonderful perennial garden, but I agree, first you'll really need to get rid of the rock and landscape fabric so you can improve your soil enough to successfully grow much of anything. Once you get rid of the rock/fabric, rototill or hand turn the soil over, spread a 2-3" layer of moist Canadian peat or a really good quality organic compost on top of the whole area, and either till it in or once again hand turn it to completely incorporate the peat/compost into the existing soil. That will give you a great start for a perennial bed--or anything else you want to plant there.

After that, we'd really need more information to make many recommendations. How many hours of direct sun is the area getting this time of year? And what zone are you in? Here's a link to a map where you can figure out which zone it is--it looks to me like you're somewhere in z4. Is there any particular height or type of plant you're looking for. Any colors you do or don't want? Is this an area you're willing to water well once a week after you get your plants in and they have time to get established, or do you want xeric things that won't need much supplemental watering once they're established?

I'm kind of wondering why your sedum--which will grow almost anywhere--isn't doing well there---if you've got hot afternoon sun, that should be enough, unless it's only an hour or two. And if your soil is so compacted that even sedum won't grow, you'll definitely need to improve it before you even try to grow anything else. And I'm not sure what you mean by "was once an edge." Was it walked on a lot, compressing it even more?

You could save the rock and put it back down after planting what you want, but I'm not at all a fan of rock mulch, and would recommend getting rid of it and mulching with bark or one of the other wood mulches which are MUCH easier to rake back when you want to plant more or dig something up to move it or divide it. If you really get into perennial gardening, you'll find it's not a one-time thing---it's an ongoing process that's a LOT of fun.

If you decide you're game to roll up your sleeves and get your hands dirty (and your muscles sore), give us some more information, and I'm sure you'll get lots of recommendations.

Good luck,
Skybird

Here is a link that might be useful: USDA Zone Map

If your soil is very serious clay you must be careful when you work on it. There's a time between greasy, sticky stuff and baked solid when it is quite friendly to work.

Even if it only goes into chunks to start with it will be opened up to allow air and compost in.

As an experiment on your soil, you might want to add some sharp, gritty sand in a small area(about a square yard)to see if it improves the drainage/aeration.

For your first year, work with annuals such as marigolds and petunias. They put out plenty of roots and will help to bring your soil into a better condition.

While the soil is still warm and workable - dig it over in autumn, add some more compost, plenty of autumn leaves - and leave it to the frost to break up the clods.

You know you're getting somewhere when you start to see worms working through. And when the clods break easily in your fingers.

Then you've got all winter to think about things to plant...

Thanks for all your help. I think I'm going to take Vetivert8's advice and do annuals this year and work the soil...then do a perennial garden next year (I'll probably be back with more questions then..lol). Thanks a bunch!

Annuals are a good idea for the first year...
But remember that whatever you plant, you will have "frying" problems with the western sun reflected from the garage wall....so water well and give some space between the plants and the wall.
And I wouldn't dig the bed....I would remove the rock and fabric and do a "lasagan garden" sort of thing there....by next spring you will have a great place to plant...
But then, I'm lazy.
Linda C