Japanese Black Pine As A Single Flush Pine
Over the years, several students of mine have said that decandling didn’t work for them. Not that they didn’t get the technique (which is complicated, admittedly), but that the results were erratic.
After going through the variables—good sun, not shaded, well fertilized, watered well, winter storage not too cold—I asked one more question: “Where do you live?”
They all lived in interior, cold, continental areas, high in elevation.
Japanese Black Pines love heat. They love sun. They’re not into cold as much as other pines. And if we decandle them in spring, we need a good long growing season on the other end to regrow another set of needles. In the case of a short growing season, a greenhouse could extend it a few weeks on either end and allow decandling in these colder regions.
Which leads to two options. Either skip years, perhaps decandling every other year to maintain some tree density and shorter needles while boosting tree strength, or don’t decandle. And accept leggier Black Pines.
The two groups of needles on the left were from not decandled shoots. The two on the right from decandled shoots. From the left, they measure 5”, 2.5”, 1.75”, 1.25”. The 5” needle was grown in a large pot with lots of fertilizer, about the same length as a freely growing pine in the ground. What’s interesting are the two in the middle. 1.75” is about right for a decandled tree to have enough length of needle to maintain plant energy. The 2.5” needle, while longer, came from an non-decandled tree kept in a small pot.
Single flush (no decandling) of Black Pines might seem wonky, but the practice of decandling is less than a hundred years old. It’s not that crazy. Expect it to be loose, like an Austrian Black Pine, but tighter than a Ponderosa. It will have a longer needle.
The trick would be to keep the needles as short as possible without endangering the plant. How would you do that?
- Reduce fertilizer—especially in spring, then increase in fall
- Don’t overwater
- Keep in smaller pots
- Repot less frequently
- Plan for a larger bonsai
- Keep up a pruning practice in fall to maintain interior shoots
Not decandling can play well for bunjin. Many bunjin are long-needled pines maintained without decandling, such as red pine.
In warm, long growing season areas, decandling is standard for maintaining dense Black Pines with short needles. It should be our assumed technique for its multiple benefits. But if it’s not working for you, look at your season length, and either use a greenhouse to give more growing days, or perhaps go rogue and skip decandling. And then maybe reconsider the shohin idea.
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