plums & pluots:

peaches:

(and, by the way, what eats those round cutouts from the peach leaves?!)

I should mention that I live in a marine climate and it has been very humid and somewhat warmer than typical this year. Also, there is a purple-leaf ornamental plum on the property behind me, near the fence line, that has declined over the past few years and is mostly defoliated by this time of year.

Fungus, bacteria, bad karma?? I tried a probably-too-late spray of copper on the plums/pluots and sulfur on the peaches just to see if I could affect the new growth. The new peach growth looks better than the new plum growth, but just a little.

Of course there is water stress this year also, but that's likely to be an ongoing issue now. Can I save these trees?

I'd say your trees are nitrogen deficient but also probably have bacterial leaf spot. It could be all leaf spot, or possibly none. Nothing for certain in my mind but some ideas to test.

I have fed these trees the same as my apples, cherries, etc. and those look OK, but with the fine sandy soil it's sometimes hard to compare even trees that are planted right next to each other. It's a little late to be feeding now, but I'll keep that in mind.

As to the possible bacterial leaf spot, is there something you'd recommend for the home grower (other than "plant resistant varieties")? I used lime-sulfur on the peaches during the dormant season and copper on the plums/pluots. Maybe I need to make additional sprays during the growing season?