When looking for the perfect tree to train for bonsai, the Japanese Black Pine should land on the top of the list. This strong tree responds quite well to a number of techniques while providing excellent growth characteristics. Because of the Japanese Black Pine being so hardy and versatile, it makes a great choice for beginner or advanced bonsai enthusiasts.
Keep the soil well drained and a mixture of 50/50 pumice and akadama. If you have a younger Japanese Black Pine, then you should add a little more grit whereas the more mature trees like more akadama. The key is to go with soil that drains well to eliminate the risk of root rot. In addition, the Japanese Black Pine must be kept evenly moist, never too damp. In fact, when watering, we suggest you keep the soil a little more on the dry side in that this tree can withstand some drought. Just remember that water for the Japanese Black Pine should have a pH level between 5.5 and 6.5 for the best results.
The Japanese Black Pine loves full sun and in the summer time, can easily tolerate temperatures of 100 degrees or more. Keep in mind that when kept in full sun all summer long, the color of this bonsai tree will change to a green/yellow color whereas in the shade or partial shade, the color would turn a beautiful, deep green. Because the hot sun can cause the bonsai container to become too hot, thus baking the tree’s roots, you should cover the container with some type of material that can block out sun.
During the springtime, the Japanese Black Pine must be significantly pruned. Interestingly, while other deciduous trees need to be fertilized, this species does not. However, this type of bonsai does appreciate products like Bio Gold in mid-spring through early fall. For pruning, this would be performed in late fall or early winter to help stop sap bleeding. Once a branch has been cut off, use a sharp knife with putty cut paste around the edges of the wound.
The key with the Japanese Black Pine is to work slowly. In fact, training of this type of bonsai tree should take place over several years. Unfortunately, dramatic pruning causes too much stress on the tree. Then, once the tree has been pruned, make sure it stays in shade for about three to four weeks. Additionally, the Japanese Black Pine should not put in locations where there are extreme temperatures.
To help promote ramification, shoot trimming should be done but only after the growing season is over. While you can prune this tree in the fall, be sure this is done only on well-fed and mature trees. Typically, the best time to wire this tree is late in the wintertime. Wiring any other time of the year causes sap leakage, which damages and even kills branches. The repotting schedule for the Japanese Black Pine depends largely on the region in which you live. For this, you would need to talk to your local gardening center or nursery for the best advice. Regardless, be sure you do not remove too much root at the time of repotting and be aware of root feeder channels during the trimming process.
For the Japanese Black Pine, you want to rearrange the roots gently each time you repot the tree. This tree will need good surface root structure as well. Once the tree has been repotted, it should be set in partial sunlight or bright shade for about three to four weeks. Finally, the red spider mite is an enemy of this tree, attacking stressed or weak trees. Therefore, make it a part of your overall maintenance to check for these insects weekly, appearing as red specks on the tree’s needles.