Hello, and welcome to GoY.
As a start, you might like to scroll to the base of the page, and click on R for Rockery Ideas, and S for Shade Plants...

I hope that helps :o)

Most plants which like rocky places also like full sun, so a shady place is not a good site for this.

Have to agree with Bamboo rockery, or alpine, plants grow in full sun on a mountainside - stick them in shade and they will sulk. Consider a woodland bed instead.

I've done some more thinking about this for you...

Last year I made a gravel garden with some rocks on an area alongside my long shed and it is a very shady part of my back garden.

You can see some photos of this towards the end of my blog : http://www.growsonyou.com/terratoonie/blog/14622-ready-to-celebrate-heucherellas-and-other-fellas

You don't say whether your tree is deciduous or evergreen ...

provided you could cope with leaves falling on the area, you might be able to take some ideas from my shady gravel garden and adapt for your use.

Terratoonie - alpines will NOT cope with shade...

No... alpines won't cope with shade, but other plants could be put between rocks. All the plants I have in my shady gravel garden, with rocks, are doing well ...

VINCA would do OK there but not look up to much. A rockery in that position would be very dry as well as shaded. I inherited one under a large sycamore and quite honestly it was a dead loss. I would have a rethink if I were you.