Ground layer
From BonsaiWIKI
Ground layering is a type of propagation layering performed on bonsai to improve or correct the root system. The technique is nearly identical to the one described in the air layering article, except rather than suspending rooting medium in a bag, the layer is located immediately above the soil, and a short wall is built up on the soil surface surrounding the layer, filled with bonsai soil. Over time, a second root system will develop within the fenced area.
Ground layering was used as a propagation method for hedgerows performed by making a cut approximately 1/2 way through a low branch, wedging it open with a stone and pushing the wound area into the ground a foot or two away from the plant. The branch produced roots at the wound site and so extended the length of the hedge by a couple of feet. In this way, a few plants spaced at regular intervals could serve as hosts to create a wide perimeter hedge over a number of seasons.
