Popularly known as the Japanese black pine bonsai, this is one of the most popular bonsai tree types that emerged from the prolific species of pines. Pinus thunbergii on a scientific stand point, these trees are monoecious, coniferous trees that can go as tall as 40 meters. They are also perpetual in nature, thus they can be around for a very long period of time. These species of pines are natives and predominantly growing in Japan particularly in Shikoku and Kyushu islands with a small population growing in the shorelines of South Korea.
Japanese black pines have long been cultivated in Japan since the 17th century. The plant was able to reach the United States in 1915 when a specimen was imported as part of the Pan Pacific Exposition. The same tree is amazingly alive until today and is located in San Francisco. The propagation of these bonsai reached its peak in the 1920’s when Japanese enthusiasts brought these bonsais to Southern California. Since then, the tree species has been a part of California’s bonsai and tree culture.
This tree species is grown by most bonsai enthusiasts due to its distinct features making it worthy of the title as the “King” of bonsai. The most predominant feature of this plant is its silvery to black bark with deep fissures, thus the name. Its dark green, string like leaves usually grow in bundles that make up its beautiful crown. Its branches grow horizontally creating a picturesque and stunning silhouette. Come Spring, this pine produces orangey to yellowish cone that bears magenta seeds.
The closest variety related to Japanese one is its European counterpart, the European black pine or the Austrian black pine. Both of these varieties share most of the features of this species. They only differ in place where they originated. Aside from grayish to black bark which is common to all species of black pines, the Austrian one has a subtle touch of reddish hues on its scaly and fissured trunk.
These bonsai trees are categorized as follows:
These trees generally tolerate a lot of sun. It is important to expose them to sufficient amount of sun to live healthy. Thus, they are not meant to be stored indoors. When the season of fall comes, the plant grows a lot of leaves. It is recommended to prune or trim excess leaves to allow sunlight to penetrate through the plant.
Regular soil composition is the best way to go for your bonsai. The soil must not be fully compacted to allow sufficient air circulation. For better nourishment and resistance to pests and diseases, it is suggested to introduce fertilizers to the soil. Monthly fertilization using an acid based fertilizer with half of the recommended dose is suggested to keep the plant healthy. However, during winter, feeding of the plant must be cut down to every other month.
Aside from being tolerant to excess sunlight, pines are also tolerant to dry soil. Overwatering is the last thing the black pine would want. In order to avoid over watering, secure a pot with good drainage to drain excess water. It is best to schedule watering the plant once every day. To have a better estimation of the moisture content of the soil, you may buy some cheap portable moisture meter.
The bonsai trees must be periodically repotted during early spring. During the repotting process, use a soil mixture consist of approximately 75% aggregate materials with 25% organic component. It is good to exercise extreme caution when pruning the roots while repotting as they are slower to grow compared to other species. This will lessen the requirement to repot it more often.
Use annealed copper of soft aluminum wire when shaping your Japanese bonsai tree. Their branches are relatively flexible, thus less efforts will be necessary to let them grow in your preferred shape. In order to prevent intrusion of wires to the barks of the plant, it is best to wrap the wires with nursery tapes. Just like other bonsai specie, a careful eye is necessary in watching the wires. Despite of being wrapped, wires can still penetrate the plant of not examined carefully.
Early spring is still the best time to do pruning. You can start by pinching new buds that will let your bonsai stay miniature. Pines are known to focus their growth on the upper tier of the tree leaving the lower portion less attractive. On this case, candle pruning is the best method to address the concern.
Black pine bonsai may be propagated from seed that are abundant during the month of April. If you are planning to start growing pines beyond this month, you can do so through stem cuttings.