AusBonsai

Good morning all,
I amm just looking for some direction to to take with the health of one of my JBP's. After a full growing season, one ofmy Pine's appears to have struggled to darken off.
As can be seen from the images attached, the needles appear to be a more of washed out flourescent green rather than the deep healthy green of a regular black pine. (and the rest of my JBP) I'm curious what the cause is and what I need to do to rectify the issue. My suspicion is a lack of a trace element in the soil.
I water when needed, pretty organic soil and was repotted in 2021. I'm very doubtful it's the health of the roots as they appear to be very healthy with a large amound of Mycorrhiza. Thanks in advance all.

Apart from the colour just looking at the bottom of the pot. Looks to need a repot and a feed.
Have you pulled it out of the pot to see the roots?
Cheers
Kirky

As it is only one pine that is affected we can probably rule out starvation or watering issues or they would all be similar.
That leaves something affecting just one pot.
Could be pot bound as Kirky has suggested. Mine definitely struggle to stay healthy green after a couple of years in the same pot Usually some extra soluble fert helps bring them back temporarily but repotting is a longer term solution - more spaces for water, fertiliser and new roots to get into the pot.
Harder to diagnose trace element deficiencies in pines as they don't have the same veins in the leaves that broad leaf trees do. Nitrogen deficiency is common and causes yellowing of foliage. Iron is another common cause of yellowing and gets worse when soils have higher pH (alkaline) which can be caused by high pH water supply. Most good fertilisers have trace elements so deficiencies are less common when fert program is good.

What fertiliser and how often this summer/autumn?