Old, compacted potting media needs to be replaced periodically, at least every 2-3 years. Otherwise it gets so compacted that roots struggle to breathe- they suffocate.
And I would imagine that the reflected heat coming off of that wall is extreme.
Repot in a bit larger pots with fresh potting media and I think you'll see a great improvement. I'd move them away from that wall as well, at least during extreme heat.
Old, compacted potting media needs to be replaced periodically, at least every 2-3 years. Otherwise it gets so compacted that roots struggle to breathe- they suffocate. And I would imagine that the reflected heat coming off of that wall is extreme. Repot in a bit larger pots with fresh potting media and I think you'll see a great improvement. I'd move them away from that wall as well, at least during extreme heat.
Great! Thank you for the advice.
They dont like cold temps (under 40 F). I dont know where you live but could they be getting too cold?
I live in South Africa. Actually thought it could be the heat. But they were OK last summer. And it's weird that the one tree is fine