True rock gardens are alpine in nature, and tend to be full sun.

Your situation sounds like a perfect place for a woodland garden, with plants that like the shade. There is nothing wrong with incorporating rocks in a woodland garden. :)

Rick

The natural rock gardens would, most likely be alpine, or like the burren, in Eire, but no rules need hold you back. Mine gets half sun and half shade and has plants that stay below one foot in height, as a rule.
But it is advantageous to use the largest rocks you can manage. Of different sizes and in natural looking strata. Mixed,or water rounded rocks look strange. Similar sorts in strata or layers seem natural. Tilt them back, very slightly, so rain runs into the garden, and not out.

Good advice bogturtle.
Shade plants tend to cover the rocks more than small sun liking plants. However, I have seen sedums growing in moss on the north side of cliffs in the Olympic Mountains here in Washington State. Moss and sedums grow quite well together here.
As bogturtle says, "It's advantageous to use the largest rocks you can manage", especially in the shade. In your case I'd go heavy on the rocks and good rock placement and use moss and sedums. Without the rocks I'd just go for a shade garden.
Mike

{{gwi:369810}}

I have a woodland rock garden, reminiscent of a naturally occuring rock outcrop that you might find in a forest. The rocks are liberally coated with moss, small creeping sedums in the crevices, ferns and violets tucked in voids and in the spring there are small bulbs and wildflowers; snowdrops, anemones, early crocus, species daffodils, etc. All this in an area about 15' across. I have also incorporated a mossy, weathered log and a dwarf Japanese maple grows behind it.

All rock gardens don't have to be sunny to succeed.

Sandy