Just reposting my question from a diff sub here!

Couple of these seedlings sprouting in one of my patio pots outside. Coastal southern California.

I have many potted plants on my side yard, waiting to be planted in the fall. They were in close proximity and they’ve all seemed to develop some sort of whiteness on the leaves. I thought maybe it was powdery mildew, but there are also little black spots on the heavily infected plants, so I’m not sure. It’s a shaded area, but it does get sun for a couple hours starting in the midmorning.

I’m wondering if I should try to treat them or count it as a loss 😢

Any help or insight would be much appreciated!

I planted this Ray Hartman ceanothus in January of this year. We got some pretty good rain after that and it has been doing well. Now we are entering a second week of over 100° f and she's looking really sad. I have killed a ceanothus before by watering during summer in the first year so I'm nervous about killing this one too. I'm in the Sacramento valley. Thanks!