A Bonsai Progression:
Hacked Away
This group shows plants ready for further developing. The over long shoots have been trimmed back to allow the trunk shape to be seen. In growing bonsai, the trunk is developed first, branching second, foliage last. Branches and foliage can be regrown but the trunk is harder to maneuver. Keeping in mind the triangle form, the upper branches are trimmed back to allow the plant to spend more energy on the lower branches. As the lower branches thicken, so will the trunk to support them.
What often happens is a trunk will develop with very little taper (a “telephone pole” trunk). With many species, the trunk can be chopped down and the top regrown. The tree is allowed to grow freely until the base is close to the desired size, at which point the trunk is cut down. The trunk can either be cut to 1/3 (ish) of the desired final height and the grower can hope for a branch to start at the top to be trained as the new top, or the trunk can be cut to just above a branch in the desired place and the branch trained to grow upwards as the next part of the trunk. This is called “trunk chopping” and is often done more than once to obtain more taper. Portulacaria do well with this, species such as pine do not.
