Old JBP Turned Greenish Yellow Color

kidrising

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Hi All,

I got this gorgeous Japanese Black Pine in an auction last July. At the time it had a rich dark green color and short needles.

I had continued to fertilize it using bonsai gold. By winter time, the needles were longer but still a rich dark green color. I had only just removed dead needles but otherwise no major work on it. Usually I try not to touch a new tree in the first year just to see how it acclimates. I did try cutting a few of the candles after I got it to see how it responds and it did sprout new short shoots no problem. But it was not a full decandle. I also did not needle pluck.

Then around the December time frame, I saw the needles started to turn a greenish yellow. First it was on the back lower side. I tried rotating the tree thinking that it was due to insufficient sun. Over the next month, the entire tree turned this greenish yellow color. Note that the needles do not pull out easily (like old needles that have turned totally yellow).

Note that I live in the bay area and this winter we had HEAVY rain. I'm thinking that has something to do with it. Other JBPs in my garden seem to be doing fine but I had recently repotted those with boon mix.

Starting in February/March, it started to put out new candles. These new candles seem healthy and green. I was waiting to see if the rest of the tree would change back to dark green but it hasn't. I've fertilized through the growing season.

Does anyone have any advice as to what could be going on? Also, should I consider needle plucking now (obviously there are too many needles now)? Or re-potting (out of root concern from too much rain)? I think I was too timid just letting it sit for the first year and now it's not quite the right time of year for either of those but maybe I should start need plucking and/or repotting? I was also thinking of holding off on de-candling out of concern this year.

I really appreciate any advice. This is the nicest tree that I have and I really worry about what to do next.
 

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Scorpius

Chumono
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Beautiful tree. I'm really upset to see it in its current state. There's definitely something going on with the roots and I'm going to say it was overwatered or kept to wet for too long.

Have you taken it out of it's pot to inspect the rootball? When was it repotted last?
 

kidrising

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I just pulled it out of it's pot to take some photos. Note that it was watered this morning. I'm not sure if there are any obvious signs of root rot or root aphids. Please let me know what you think based on the photos.

I'm not sure when it was repotted last. The auction was from an elderly bonsai teacher that was selling a massive collection. It's possible it's been a while. It definitely drains slower than my other JBPs. It also looks like there is more organic soil than the typical soil mixture I use. I agree with the thought that it was overwatered from the excessive rain we had. Do you think it's worth repotting with equal part akadama/pumice/lava rock mixture now? Or wait until next early spring? I've also heard of repotting 50% of the root ball.
 

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Scorpius

Chumono
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That looks like straight up miracle grow potting mix. If that's the case I question why for the previous owner? Especially on a tree of this size it should be in more suitable bonsai substrate. We're heading into the heat of summer and repotting is usually a no go then, but in emergencies I have repotted in the dead heat of summer with mixed success. Right now the tree is stressed and repotting either stresses it more and kills it, or it fixes the issue and recovers. Doing nothing and the tree more than likely dies.

If this was my tree, I would repot, but I would not trim any of the roots. My goal would to carefully remove a good amount of the potting soil while not touching the core of the root ball and replace with proper substrate to let more oxygen to the roots and improve drainage. I would also drill more holes in the bottom of the pot, switch to plastic or mica pot, and after repotting keep the pot tipped up on one side which prevents pooling of water in the bottom of the pot.

I don't want to lead you down the wrong path so I would wait till someone more experienced chimes in this thread.
 

namnhi

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Not sure if the color in the photos show the true color of the tree but they looked really yellow to me. The good thing I see are the active root tips which showing the tree is still alive. I would seek out the experts in the area for advices. This is a really nice tree. You in the Bay Area... do you not have access to Boon, Jonas or Eric Shrader?
 

kidrising

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Thank you both for your feedback. Yeah the potting mix does look like miracle grow. The previous owner though was known for growing beautiful JBPs like this so I assume he knew how to make it work. He also lived in the bay area. Maybe it was just my microclimate not covering it from the heavy rain that resulted in issues. I’m sure the more free draining mixture would have been more forgiving of the heavy rain.

I think the repotting method you described with minimal root disturbance sounds like a good idea.

I have met Jonas and Eric at some shows. I think I will reach out to Jonas since he was always super nice and doesn’t live too far away. Definitely getting an expert opinion seems like the right way to go to give this tree the best chance of success.
 

Dadayama

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Hello Kidrising
Where you able to save the tree?

I wish i would have saw this earlier but to me it looks like chlorosis which would be cause by a high pH soil. Most trees like to be on the acidic side of the neutral range. This is a problem for potting soil if it is not maintained.

Hope you saved your tree
 
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