The semi-cascade style or han-kengai is similar to the cascade style, except that this time, the trunk and the apex does not dip below the level of the container or pot base, even though they also grow outside the confines of the container area just like in the normal cascade style. The trunk of the semi-cascade also oftentimes does not bend more than 45 degrees below the horizontal level base of the container in which it resides.
The problem is that this style is not very well defined. A few bonsai artists maintain that the semi-cascade style should be allowed to project below the “ground level” of the container. Most bonsai artists however, concur that the semi-cascade style should not go below the “ground level” and if you look at the creations of many semi-cascades, many do not even drop below the upper top of the container. The pic shows a Mugo Pine about 100 years old, which exhibits the semi-cascade style to good effect. The important thing in the semi-cascade is that the tip or apex of the bonsai tree should always stay somewhere between the top rim of the container and the base of the container. As long as it lies within this zone, it can be classified as a semi-cascade.
The other aspects of the han-kengai are similar to the kengai. You will need a deep container or pot for future stability and the bonsai tree needs to be planted “off-center”. The choice of species to use is important as well, and Junipers are considered the most suitable species for the semi-cascade, as are flowering cherry trees like the Japanese Sakura, which will produce a nice blossom spectacle in springtime. Weeping willows and chrysanthemums also make good choices for the semi-cascade style.
It’s important to ensure that the slow-moving nutrients make it to the tips of the branches, which is not so easy for bonsai trees grown in the cascade or semi-cascade styles. Foliar feeding is easily accomplished for this purpose, but needs to be done regularly as part of the watering and feeding practice. The top portions near the apex need regular pruning to ensure they don’t overshadow the main lower branches.
The semi-cascade (as well as the full cascade) is quite popular amongst fairly experienced bonsai artists as they project the visual impression of a tree leaning out from a cliff or stream edge and reaching for the light or water, and immediately identifies the tree as a bonsai-grown tree to anyone that see it. Due to this style not being easy to achieve successfully, beginners are advised not to pursue it until they have a firm grasp of all the basic bonsai growing techniques.