Dying fruit trees and italian cypress

[spock_s]

Hi
I live in Folsom, CA (suburb of Sacramento) and got my backyard landscaped 3 months ago. I think I am in zone 8 or 9.
I have Italian cypress, Guava, Peach, pomegranate and Japanese maple that are all dying. Sounds like a lot right? Well, you can tell I do not know much about tree care
The first tree to loose all it's leaves was peach. then Folsom had terrible hail storm of which the Japanese maple got a frost bite and then the pomegranate started drying it's leaves and now is shedding them slowly. The Italian cypresses have turned brown from nice fresh green. And the Guava tree leaves have curled and are drying slowly.
I have a feeling it's some sort of a bug infestation that I just can not find. I do see small black dead bugs occasionally on the Guava tree, but nothing on the cypresses so far. I also see green color flies and helicopter looking fly (sorry, don't know the name of that bug) flying around in my yard. I have citrus trees that seem to be doing fine. I have lawn in the yard which seems to have a lot of insects so I sprayed Scott's bug killer on the lawn. I also had some slug problems from the new wood chips they put I guess, and so I put the slug killer all over the yard, but made sure it was away from the trees.
Not sure what's killing my trees, Please help. Sorry for the long description
Thanks
-Spock_s

 

[LightningLoader]

Is anything still living in your yard?

Wow, sounds like almost everything you've planted is dying. My first question would be have your trees gotten plenty of water? Newly planted trees need alot of water to get established.

 

[spock_s]

dyring trees

Well, yes, there is an apple tree, 2 citrus trees that are doing fine. All the shrubs in my yard are doing fine as well except for the 1 gallon lavendars I planted. They're also dying int he same fashion. totaly drying up. I have checked the dampness of the soil by hand (not using any measuring tools) and the water seems to be going fine to all the trees. I have automatic drip system that turns on twice a day for about 3 mins each.
Can you guys provide me with any other suggestion on this please.
Thanks a bunch for your help and response
spock_s