All fruit and nut trees do better if the trunks are painted with a white interior latex paint mixed 50/50 with water. This keeps the trunk from sunburning. I imagine your landscaper wants to avoid crown rot. Check the watering requirements of your ornamentals. Those that require frequent watering should be transplanted into an area where they can be watered appropriately from sprinkler heads in one zone and set your timer accordingly. then you can adjust the timer for the other zones to less frequent watering. Your citrus probably need watering once a week, not more. Some of the ornamentals might be able to do okay with the same type program. Water deeply, but infrequently to drive roots down into the ground, not up seek water where they might cause heaving of concrete, etc.