Irregular watering. Once a week is probably not enough water. I grow all my JM's in containers - most quite a bit larger than that - and they get watered 2-3 times a week. And we never hit triple digits!!

That is pretty characteristic of containerized JM's that have been allowed to dry excessively between waterings. The soil should stay consistently moist (not wet). I'd also consider the container too small for that size tree. And the smaller the container, the need for more frequent watering.

Since it’s potted can you locate it somewhere where it gets mostly shade? It definitely looks like leaf scorch, GG is the expert but I suspect that even properly watered it will suffer some scorch like that if it’s exposed to 100 degree direct sun, morning or otherwise. Here in “cool” zone 5b an hour of direct afternoon sun regularly scorches some outer leaves on our in-ground Crimson Queen.

Thank you! I’ll definitely be watering more often now and moving my JM to a larger pot. Hope it helps!

I water if it doesn't rain for 2 or three days. If it does rain, I still water... Just to make sure ALL the soil is saturated! My JMs are in morning sun and afternoon sun. The cut leaf varieties seem to brown quicker, especially the Koto No Ito.

Hi, Just tagging onto the thread as I have a similar issue. I have a Crimson Queen that was planted in the middle of summer which turned out to be a hot dry summer here. I have tried watering regularly every day or 2 at least. When it was first planted we had some windy days even tho the area is quite sheltered. Does this look like wind burn or not enough water?

That's a water issue.