I am on a corner with steep slopes on both sides, and where there are trees, shrubs, and the remnants of both an old sidewalk and old retaining wall. I created a boulder/rock garden all the way around. It was nearly impossible to dig a hole of any size. The only way I was able to plant anything was to use small plants and find little areas to create planting pockets. I found that using half a pot often worked very well. I would purchase a plant or shrub and cut half of the pot and the bottom away. Then I would plant it with the remaining part of the pot on the downhill side to retain the soil until the roots took hold. A few months after planting I would just pull the pot out. I even left it there in a couple of places to continue to prevent erosion. You can see pictures of the project in the Garden photos thread, Problem #2 is solved. It works very well, and this article is a perfect explanation of how to do it!
