I'm recently moved in to old house in Southern California that has a 100 year old orange tree that is not looking so good. The house is almost 100 years and this tree was one from the original grove the was here. I'm told that its been several years that it had any care. I've started to water it regularity but not sure what else to do. I new to this and I've read a lot but not sure if its just from the lack of care (water, fertilizer, etc.) or if there is more going one (guess the later).

I really hope it can be saved, the fruit it does produce are some of the best oranges I had.