We have a ~25 yr old orange tree here in the SF Bay Area that started turning yellow a few weeks ago in the middle of a summer heat surge and has since has begun to lose leaves by the gross and drop the remaining oranges it held from last winter. I don't see any new fruit budding either and the top of the tree is becoming bare.
We changed the watering around in the early summer and it may be getting more water from a nearby sprinkler than it has before. We tested the soil on one side and found it very moist. We put in some fertilizer sticks and have redirected the sprinkler starting a few days ago but wonder if it's too late to save it (as you see, we're assuming it's overwatered).
add on after reading more posts about similar issues. Over the last two years, blue star creeper has been growing underneath the tree but we still leave the last 2 ft diameter around the trunk open (about 8ft diameter drip line) and prior to us moving in there was grass or moss beneath the tree. Also, back in the beginning of the summer I also tried some citrus fertilizer but put most of it directly near the 2ft ring instead of dispersed around the 8ft ring. Wasn't much. So - now what should I do???
It is very possible that those symptoms are from overwatering-- if so stopping the watering should eliminate the problem and the tree should slowly recover. Ingound trees, once established, do not need watering except during a drought.