The exposed top of the chunk of soil at the bottom of the first one, that it came growing in looks dry. Carefully poke around in that to make sure it is moist all the way through.

If you are depending on an automatic irrigation system to keep this tree watered during this establishment phase you may in fact have to supplement that with hand watering.

Also these look like they are Cornus capitata, a related species or one of its hybrid garden forms. These don't necessarily do well in sunny positions in hot climates where the root zones may get too warm for them. This could perhaps account for the differences in response between the two you are showing here, with the second one responding to being shaded by the house.

the woodside area of what or where?

Thanks for your comments. We are loacated in Woodside Hills. Few of the plants that are in partly shaded area also look sick.

I poked a few holes and the soil sees moist. It has been raining here on and off for the past few weeks so the soil is moist. The plants that are growing nicely are in 100% (ready to ue) soil I purchased from Garden Supply. The sick plants are in mix of purchased nursey mix and native soil. Fertilizer (ones that look like tea bag) was also mixed with the soil.

See what I said on the duplicate thread. Otherwise rainfall cannot be assumed to be adequate for even well established plantings, that have rooted fully into native soil unless there has been a minimum of one inch per week.

We had no rain for months after these plants were planted last summer. They were watered with a drip system 3 times a week for 12 minutes. That may not have been enough.

I am going to start watering them by hand. Are these plants sensitive to over watering?

Do you have any other recommendations for saving these plants?

Dig the sick looking ones up and replant in unmodified native soil. The healthy looking ones that got a different treatment at planting, judging by the shot near the house may even have rooted in by now can be left alone.

Thanks Embothrium!