About my Japanese black pines

Hello Mr. Dupuich,

I come again with the questions and the pictures you have asked for.

  1. If I have not decandled my Japanese black pine this year ( in June ) could I cut the sprouts of this year, this autumn ?
  2. The needles of one of my Japanese black pine have turned yellow. Which could be the cause of this ?
  3. I know it is not the best moment for repotting, but could I change the soil of one of them ?

With many thanks,
Septimiu !

Thanks for posting - I see a few things going on with this pine. First, your questions:

  1. Fall is a good time for pruning, but not for decandling. Removing new candles in fall can lead to branch dieback.

  2. The needle color likely reflects a problem in the roots. If there is old soil in the pot, this could be the problem. The problem could also be caused by a fungus. I would start by repotting and see how the tree grows in spring.

  3. I would wait until the end of winter to repot. If you live where winter is mild (no snow or frost) you can repot in December. If winter is cold where you live, it’s best to wait until the end of winter. If you decide to repot early and it is cold where you live, you will need to protect the tree from the cold until spring.

I also see that the tree has pine needle scale. You can pick these off by hand or try oils or pesticides to control them. Now is a good time to treat the scale.

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Hi Jonas,

thank you for the information !
You are right. It may be a soil problem. I have not changed it for about 4 years.
I am going to do this next spring, because we have very cold winters here.

With my best regards,

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