Chinese Elm yellowing/spots

Hello

I have 6 Chinese elm trees that I grew from seeds. I’ve had them for about 6 yrs. Every year starting around mid summer they develop these brown spots on the leaves. At first I thought it was a disease and it would wipe out the trees, but it happens every yr.
This year the leaves are starting to turn yellow as well on some of the pots.
Last yr I did repot them in smaller, shallower pots. I just watched the video by Ryan about watering. Now I know the trees suck up water in our hot, dry southern CA weather since there is a lot of foliage and smaller pots. So I’ve been paying closer attention to the watering lately.

Can anyone tell me what this is please? The internet sucks for finding valuable information. Lol

Also I was planning on air layering a few smaller branches as the goal for these trees is to create a forest style on a slab.
I wanted to air layer this coming spring but not sure if the trees are in great shape. :frowning:
Is it better to air layer before the new buds come out or after in late spring? Again, with hotter, dryer climate?
Please help?

My cork elm hasn’t had this issue. The only thing mine has is that some leaves turn yellow …I started giving mines osmosis water and it stop turning yellow… even thou is been as hot as any other day. I live in Los Angeles it’s about 80 degrees + these pass few weeks. Maybe the water from the hose have strong chemicals. Try osmosis water and see if that helps.

That’s a good idea, thanks…yea our water is shit. lol. I know it has a LOT of calcium, as there’s always the white residue on the hose tips, etc… Not the best.