you dont say how recently they were planted...

but you must understand.. that even in z10.. it's winter ...

i would suggest transplant shock .... plus winter ... and perhaps improper watering[which includes no mulch] ...
before i would go spraying a very stressed plant with chemicals ...

take a hand trowel.. and go dig a 6 inch hole.. on the edge of the root mass.. and tell us if water is being provided thru the root mass .. at depth ...

and also explain your watering protocol ...

proper watering should be deep and thorough ... and then near drying before you water again ... and then the mulch will insure a cool surface and retard fast evaporation of the surface ...

if i planted a plant that size.. in my high drainage sand.. in late spring .. and mulched properly .. i might not water it again.. for a month ... how often are you watering ... how long.. and how deep is that surface watering getting ...

stressed plants are more susceptible to disease.. but if you dont fix the stress.. fixing the disease wont help .. and applying chems/org solutions.. might only increase the stress ...

ken

Shot hole fungus (you can find control recommendations searching the name online) looks like you fired a shotgun through the plant. The reddening etc. shown here will be something else. I'd see about taking samples to the nearest California Cooperative Extension office and getting a diagnosis.

Thanks for the replies. These were planted in the backyard toward the end of September. The soil that they are planted in is a relatively thick clay. The drainage in this area of the yard is poor. We confirmed the drainage issue when the holes for these plants were dug, and we filled some of them halfway with water. Where the drainage was really bad, the water barely budged after 24 hours. In other areas along the wall, the water had drained completely after 24 hours.

As time passed after planting these, they did begin to get a shotgun hole appearance. This really only impacted the plants toward the middle of the row. It then began progressing where instead of just holes, larger portions of the leaves began turning red and becoming very jagged in appearance. This is now beginning to expand toward the other plants on the ends of the row.

The watering protocol is we watered them heavily for the first two weeks. This was watering them for approx. 8 minutes a day. We then cut back the watering, as these are supposed to be relatively drought resistant plants. Combined with the poor draining clay, I have all but stopped watering the plants. We have had some recent rain, which I thought would be sufficient.

As a first step, I'll follow Ken's advice and go check 6" down along the root mass to see if the impacted plants look like they've been getting enough moisture. I'll post a follow-up with the results.

Thanks again.

Red spotting can be associated with excessive moisture, that probably is your problem.