Losing Trees: Corkbark Japanese Black Pine, ‘Kyokko Yatsabusa’

Here is a post from 4 years ago when the tree looked good.

https://nebaribonsai.wordpress.com/2019/09/21/fall-cleanup-on-a-kyoto-yatsabusa-corkbark-jbp/

The tree has a weak root system, and I ended up planting it in the ground to strengthen it for a few years. When we moved in December, I stuck it in a pot. It wasn’t much healthier, and the lack of roots was alarming.

In March, buds were actually swelling, and it made it through winter, so I figured I’d at least give it a fighting chance.

The lowest branch did die, but it was a debatable feature that made the decision easy.

Unpotted, check out all those roots.

Using a few screws and chopsticks to create some anchor points, I managed to secure the tree to the pot.

Notice the deep drainage layer of medium-grain akadama. The layer of soil used in the zone where the roots are is a more retentive mix of akadama, pumice, and lava. The top layer included more Kiriyu sand so the top third isn’t as retentive since it has no roots.

Repotting completed.

Next up, dead stuff and old needles removed, and new needles reduced to 12-15 pairs around extending candles. I also removed weak shoots and excessively strong shoots and removed all old wire.

Finally a couple pieces of wire to gently moved a couple shoots into position.

One more shot with a deeper background.

Spring work done, now I hope and feed heavily for some good growth. Unfortunately, by mid April, it was clear that the tree wasn’t able to survive the move. As soon as we had some sunny warm days, the green foliage got dull, then gray, and finally the straw-color that is hard to look at on the bench. RIP.

A telltale sign is when the soil stays wet, and the trunk doesn’t show any signs of wicking.

Parting shot of that killer bark.

Corkbark Japanese Black Pine, ‘Taihei’

Here is another corker that I’ve neglected, though it’s been in a pot and managed to stay healthier than the Kyokko Yatsabusa. It was last repotted in 2019, and this spring’s work was pretty straight forward.

Starting point, notice how full it is, and some shoots are very strong. The soil is covered with moss and weeds. Without cutting strong shoots, they’ll overpower the weaker ones and the growth will get leggy. Without pulling old needles, the growth will weaken on the interior and it exacerbates the imbalance between strong and weak growth.

This shoot has a strong bud at the tip, and a smaller bud at the base. Since it’s near the apex and at the exterior of the tree, I’ll remove the stronger shoot in favor of the weaker.

Cut

Smaller bud remains. It will strengthen, and will provide some new growth closer to the trunk.

After balancing the tree as demonstrated above, and pulling needles to ensure sunlight can penetrate to the interior.

Old soil scraped away down an inch or so, then replaced with fresh and worked in with a chopstick. Next year, it will probably be time for a proper repotting.

Finishished

And back on the bench.

Japanese Black Pine, ‘Arakawa’ update

It’s been a while since this tree was featured, here is the last post

Another year (or two) in the life of an Arakawa JBP

The variety is slower-growing than standard JBP, so I have not done any summer candle-cutting during the last 4-5 years to keep the tree stronger. This slows the development of branch refinement and results in longer needles by the year’s end, but there will be time to work on that later after the primary branches are set.

The last post left off in spring ‘22. Since then, wedge cut is healing well, and the tree is growing strong enough. Here is a shot from fall ‘22, before needle pulling:

And after needle pulling, and minor branch pruning and arranging:

Christmas ‘22 saw 4-5 nights of temperatures down to 9f overnight, and highs in the 20s f, which was 20 degrees or more below average. All the trees spend a few days in the basement to protect them from the cold. USDA Zone 7 trees in the ground took a beating, and I lost ilex serrata, Princess persimmon, crabapples, and trident maples. Rough winter.

Spring arrived early, however, and I repotted this tree to get it into a deeper pot, set the planting angle, and replace the soil with the coarsest stuff I had…pumice, lava, and medium akadama, Hopefully no more root rot issues again.

Fed heavily this year with Bio-Gold and regular weekly dousing of fish emulsion, the tree responded with good growth and dark green needles.

The wedge cut is healing over well, and while it isn’t visible in the upper crown right now, it did add important movement to that stovepipe-straight section.

In late August, I thinned out the needles, pulling old ones, and leaving 8-10 pairs of needles on each shoot.

In the late fall, it should be pruned and rewired. I am happy with the movement the tree now has toward the left; it’s a more dynamic tree, which was the goal. It’s been a slow process, but maybe local-show worthy by 2025.