Gardening and Horticulture - Dying trees -

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

if these trees were all added three months ago and are dying, you need to get your landscaper out to check them. most landscape companys will give you a one year warranty on new plantings.
sounds like they didnt get enough water to survive.

I agree - do you have a watering system? If not, your landscaper should have instructed about the watering schedule for the trees. New plantings need regular watring until they are established.....

Blessings,
Debbie Long