Japanese black pine air layering
I have been growing Japanese Black Pines from seeds for the past 7 years. Recently, I discovered it is possible to air layer them so I gave it a shot. It was surprisingly easy and I noticed some factors that I believed helped. I'll continue to review them over the years to see if they are valid.
I started the first attempt in early March and continued to make new air layers every month until late September. All the AL that started before August succeeded and the ones made late August onwards didn’t. I noticed that heat played a crucial role and the AL that were exposed to direct sunlight and heated substantially developed roots very fast. Sometimes after 2-3 weeks. I used sphagnum moss and only a handful of it on every AL. I noticed that pressure around the moss and stem was also helpful. It is very important to keep the moss moist at all times.
It's very important to use a sharp clean knife and make a clean cut. Use rooting hormone as well.
At this point, don't disturb the roots and leave the sphagnum moss intact. plant in a small pot with well drained bonsai soil.
This is one of the trees, the following season at repot.
The high success rate really surprised me and I made 12 new trees from different genetics out of 14 attempts in one season.
The one shortcoming with this method is that some of the AL developed uneven root flair. This is something I want to examine in the future. I hope to get a better understanding of what causes it and maybe how to prevent it from happening.