I never paid much attention to landscape rocks until I started a recent Japanese garden installation. Of course, the Japanese attribute a lot of meaning to the rocks in their gardens. Most importantly, the rock should represent a natural landscape. As a result, the rock needs to look like it was always there and like it belongs there. So, avoid using recently chipped or cut stone. If you can get some moss or lichen growing on it, all the better. 

And for sure, bury the rock so that not only is it firmly rooted in the soil, but so it is emerging from the soil. I have read that one third of the rock should be buried, but I think it really depends on the shape of the rock. So long as the broadest part of the base is buried, it should look just fine. All too often, I now pass a landscape that has a beautiful large boulder perched up high in a bed. It looks like it rolled off the truck and found its permanent home. I never would have given it a second thought before.  Now I think it looks kind of contrived and unnatural. So, if you want the natural look, be sure the rock is buried in the soil.

Posted by Bob Rensel