Not all trees will grow from cuttings. Ficus trees, for example, grow easily from cuttings, while Japanese maple can be difficult if not impossible to grow from a cutting. Once a cutting takes root and begins to grow, the resulting tree will end up the same size as the original tree unless the proper steps are taken to keep the tree a miniature. Growing bonsai trees is an art and a science, and it is essential to understand the basics of growing and training a bonsai before you begin.
Using your sharp knife, cut the end of a small ficus branch approximately 4 inches long. Make your cut just below a node, or leaf joint. Cut a branch with a stem diameter at the cut-point of no more than one-quarter inch in diameter.
Place the cut end of the branch into a glass jar filled with room-temperature water and leave it in a warm and sunny area, but not in direct sunlight. Cut off the very tip of the branch where leaves would normally form. This prevents the tree from getting taller, promotes root growth and encourages the plant to bush out rather than grow taller.
Pour out the water and carefully replace with fresh water every three days. Be careful not to break any fragile tiny root hairs as they begin to form.
Plant the cutting in a suitable bonsai container filled with bonsai planting mix (available from any major nursery) once sufficient roots have formed, three to four weeks after cutting. Keep the planting mix moist but not wet. Keep the new plant in a warm and sunny location. (Tips for choosing the right planter are included in the Resources section.)
Allow the new tree to grow for approximately one year before doing any pruning or wiring that makes your cutting into a true bonsai.