The informal upright or miyogi is a variant of the formal upright in the sense of being more “casual”. It is usually styled to be somewhat asymmetrical, at the expense of vertical and horizontal regularity. This style is perhaps the easiest of all the styles in growing bonsai. If you’re a beginner to growing bonsai trees, then this style is most suitable to grasp the basics fast.
In the informal style, the trunk of the bonsai bends slightly towards the right or left, while the branches are trained in the same fashion as the formal upright. The top or apex of the bonsai tree is usually allowed to develop dense twigs and branches, just like the formal, and at the same time it must always be positioned about directly above the base of the bonsai tree, to compensate for the curvy trunk.
Suitable species for the informal upright are Japanese Maple, Pomegranate, Crab Apple, Beech and most Conifers. You can choose deciduous species for the informal upright because they look good during autumn and winter time, especially if your bonsai has abundant dense branches.
Branches usually start one third of the way up the trunk just like the formal upright, but in the informal upright, this is not really “a must”. Due to the nature of the trunk that curves, such bonsai can be better off having the branches start higher up, or lower down.
The slanting trunk of the informal is achieved by training the roots of the bonsai to grow forward towards the front of the pot. Selective watering and wiring that favors the front of the container, as well as clever repotting can help in achieving this effect. When the trunk slants backwards, the tree usually tries to compensate for the gravitational pull by growing more roots towards the opposite direction, thus creating a slanting effect.
The trunk is also allowed to grow up and thicken, until after a certain period of time, when it is cut back down a few inches and the process is then repeated; each time the cut is made higher up. This method will set down a good curvy trunk that will form the basis for growing dense branches. Choosing a species that naturally veers away from the vertical should be an easier way to start in the informal upright.
Should you contemplate on growing your bonsai tree in the informal upright style, the first thing is to choose the right species for the task. Due to the common form that this style takes after, the informal upright is very common everywhere and popular with bonsai artists, both beginner and advanced alike.