Yellow needles on a JBP


#1

Hi everyone,

Last winter I got a 3-4 year old JBP that I transplanted i into a colander with an Aoki mix during the spring. I haven’t work on this tree, first because I believe that I need to learn how to maintain it alive, second it is very young and it needs to grow. It flushed during spring and late summer. A few weeks ago I noticed tbat the tip of the new needles are turning yellow. What could it be? I thought it was overwatering but root problems usually shows up in the base of the needles. BTW I am in Dallas, Tx and the weather is crazy. I attached a few pictures.

Thanks for yhe help.


(Jonas Dupuich) #2

The yellow looks like it could be a symptom of a root problem. I’m more concerned about the dark colored needles. Could these be the result of recent cold spells? Too much fertilizer can also lead to dark tips.

Making sure the roots are healthy is the best way to address the yellowing. This means using good soil during repotting and making sure the center of the rootball doesn’t hold too much moisture.

If the soil is good, a systemic broad spectrum fungicide might be a next step.


#3

Jonas,
Thank you for responding. I did not realize, but the tips are sort of dark pink (see picture attached). I the aoki that I believe is 80% akadama and 20% Kiryu. In the early fall I had to travel and left it with someone which I believe water it everyday for a week, could that be it? Cold spells?!? I am in Dallas, Today we had 18C/64F during the day and we will get 1C/33F during the night and is not uncommon to have a couple of days in the ~60s and the a couple in the ~40s. Could that be the peoblem as well?

Btw, I thought that root problems are usually reflected at the base of the needle first. Is not?

Thank you


(Jonas Dupuich) #4

Pines naturally yellow in cold weather, especially at the needle tips. The yellow needles in the second photo look weak and short relative to the other needles. These clues make me think root trouble. This could have stemmed from missed waterings followed by over-waterings.

The soil mix is good, though I typically cut Aoki blend with pumice and/or lava to get the akadama percentage down to about 30-40% for young pines. When there is more akadama in the mix, I usually water a bit less.

A number of things can cause needles to yellow at the base of the needles. When the needles yellow at the base and are healthy elsewhere, that’s a common sign that the tree is receiving too much water. In other cases it can indicate root rot, especially when combined with other signs like overall poor growth.

It’s hard to tell without seeing the whole tree, but if the general needle character across the tree is good with some yellowing, I’d guess the tree is in good shape. If most or all of the new needles are short and/or yellow, I’d try to protect the tree from freezes and avoid over-watering.


#5

I see. So the tree is weak maybe due to overwatering. And i thought that it was more vigorous due to the second flush of new needles it did during late summer. I will cutdown the watering. About the broad spectrum fungicide, what do you recommend for a weak tree? Lime sulfur, copper based fungicide, mancozeb?

Thanks for the help.


(Frank Corrigan) #6

Just wondering if the normal location is a balcony and the container is a colandar? This combination could lead to difficulty with watering and drying out, possible windburn and or more extreme effects from temperature swings. A cold spell for example may turn the needles purplish in the fall, specially the tips.
The soil mix sounds a bit heavy on Akadama and Kyru, but that might be a blessing if it in a colandar and exposed on a balcony.
From the picture i could not tell if it was a window well or balcony setup.
just some stray thoughts!


(Jonas Dupuich) #7

Following what Frank said, it’s hard to say if it’s a watering problem without knowing more about how the tree is planted, where it is kept, and what the watering habits are. Moisture problems in the roots happen to be the most common source of trouble that can lead to the symptoms you are seeing.

As for the fungicide, it’s hard to select one when you don’t know what you’re going after. Systemic options would get inside the system and can help if the problem is in the roots. Contact fungicides are helpful if the fungus is on the surface of the foliage - not necessarily the case here.


#8

The tree is in a pond basket that is 10x10x5 (width X length X depth). It is on a balcony on a second floor pointing south. Direct sunlight from 9 am to 4pm during the fall-winter (estimated). Its protected from the southbound wind because of another building in the front. I water every time I see the top layer of Akadama is dry (completely dry). In the past few weeks I am watering almost every 3 or 4 days because its been very humid and is taking longer to dry. I forgot to mention, the bottom of the basket is filled with pumice and lava rock (about 1 inch) I mix the water with a bit of vinegar and every now and then with phosphoric acid because the tap water pH is about 8 and I lower it to about 6. We have not had freezing temperatures yet, but oscillations from the 50s to the mid 30s have happen several times now. In terms of fertilizer I used solid organic fertilizer with a NPK of 5-3-3 (espoma plant tone) during the spring, summer and early fall. Then I change to a liquid organic fertilizer lower in nitrogen, 2-8-4 (Tiger Bloom), wich I apply every other week.

Hopefully all this info will help a bit more. But let me know if ai missed something.


(Frank Corrigan) #9

The additional information is very useful. In this situation, i would discontinue the use of vinegar and phosphoric acid to lower the PH. Vinegar is unstable and creates a phenomenon known as PH bounce. Phosphoric acid is very strong and difficult to mix in small batches with accurate results. Unless you are also using a correct buffering agent to stabilize prior to reducing the PH.
A simpler solution would be to use distilled water to reduce the PH of the tap water. Or simply use the regular tap water, it is not ideal but safer than inconsistent results.
I would not change anything else or use fungicides at this point. Your watering approach otherwise seems good.
I suspect if you use this approach the plant will slowly improve and recover.


#10

Thank you for the help. I will stop adding acid to the water. I should mention that I was keeping track of the acidity of water with both litmus papers and bromothymol before and after adding acid. Therefore, I do not think I have lower the pH to much. So the conclusion is… The overwatering while I was away? One week overwatering cause all this harm?


(Frank Corrigan) #11

Sorry, perhaps i needed to explain more! I was not sure that a detailed explanation would help. The instability occurs often within one or two hours after treatment with Vinegar and overnight with phosphoric acid. Unless you were testing the result after circulation or sitting for a period of time it would not be noticed. We had to modify the PH for aquarium water for a business i owned. This was to provide safe exchange water for over 300 aquariums and vast koi tubs. Simply testing at the point in time chemicals are added is insufficient. Due to the chemical makeup of the additives and the carbonate hardness of the water supply it can change dramatically within hours of treatment. Unless the corect type and amount of buffer is added to stabilise the PH. The amount and type of buffer required is differrent for each water supply based on the carbonate hardness and other components in the water. Testing the PH is only one parameter and the addition of acid is only effective if it remains at that measurement. Litmus paper can be easily affected by humidity, bromothymol blue easily affected by the cleanliness of the test tube. Electronic tester is the most reliant, if calibrated and cleaned regularily.
You probably were within the range, however plants dislike abrupt changes and even moreso if it fluctuates up and down. i would still suspect the water prep as the main issue.
One week of overwatering in that type of container and soil mix should not be the cause.


#12

Enlightening. Thank you.