Bonsai from starterplants
Making Bonsai from starter plants is a much used technique to speed up the process of creating Bonsai. In Japan you will come across fields where starter plants are being cultivated specifically for this process. One of the biggest advantages to start growing trees in full earth is that the tree will develop faster than in a pot. Also the trunk will thicken much faster which is an important aspect to create a nice bonsai. One can also use young trees that are grown for gardens in commercial nurseries.
Bonsai field in Japan
These young trees are then shaped into the desired style by pruning and wiring. There are different techniques to ensure that the base roots and the trunk thicken in an optimal way by for example growing a sacrificial branch. This lower branch acts as a sap-puller and will thicken the trunk at the base. Hereunder a video where Peter Chan shows how easy it is to shape nursery trees into Bonsai trees.