I was on my way home from a funeral in San Jose CA and on Hwy 680 I saw an oak on a steep hillside. It was an amazing specimen and was wondering how to recreate the effect with a bonsai. The problem was that the main branch on the trunk on the side farthest from the hill swept down below the root line. To copy that in a bonsai you would have to place the tree to one side of the pot and let the branch droop below the pot line but that would be unaesthetic since the tree would be off centered in the pot. So how could I do that without mounding soil up to create an extreme hill?