Bonsai growing: Root Over Rock. Root system
Bonsai is that very garden art which tries to imitate the objects and processes seen in nature. For this reason ‘root over rock’ style has been widely spread among bonsai-lovers. The roots of trees grown in this style are forced to ‘cling’ to and grasp a rock - and then to disappear into the soil. This style imitates growing of a tree in a small rock cleft when the tree tries to find more nutrients. When the roots get into soil, they harden up and grow ‘around’ the rock and the roots start to act as the tree’s trunk.
The first step for a ‘root on rock’ style is to prepare everything necessary. In this case plant and rock are equally important: you should find a suitable rock for this planting that looks attractive, natural and has suitable size for your plant. The tree which you are going to use should also be healthy and have extensive root system. You will need a plant with long, strong roots that will grow over the rock. If your plant does not have a very long root system, you can encourage growing of roots by planting the tree in a tall thin pot. Grow the tree for about a year until it will have long enough roots.