There natural soil in where we collect them from is a combination of fine dirt and rocks of all different sizes. And each dig varies from a little bit of rocks to a whole bunch of rocks that you will encounter for each tree, but what I have found, is the trees on hilly slopes seem to have more rocks than trees collected from a flatter area on the mountain. Overall, the soil is not that great that they naturally grow in, so we like to get rid of as much of the natural soil as we can, and replace it with a lava rock pumice mix and the trees seem to really like it.