http://edis.ifas.ufl.edu/ch142

might need some fertilizer. nitrogen/magnesium?

how much rain/water has it been getting?

In December we received 15+ inches of rain (hence the mudslides that made the national news). Since then I have watered it once a week fairly heavily.

The leaves on my navel orange look EXACTLY the same. The funny thing is I get alot of flowers and good fruit.

I have my tree planted in my back yard in my lawn. I have a circle of just dirt around the base of the tree but I think the grass is stealing the nutrients from the tree. Im planning on cutting more grass away from the tree and feeding it with a 20-20-20 fertilizer I have with tons of micro nutrients. Plus I think I have been a little to liberal with the water. The grass dries out so quick and while Im water I water the orange tree as well. Im sure it is from lack of nutrients and possible over watering.

Probably a combination of a lot of water, cold temps and some chlorosis. Check down to see really and truly how wet the roots are. If they're soaked, stop watering for a bit. Then, give it a very good fertilizing with micronutrients and hopefully your new flush will green up. The older yellow leaves may drop, but you'll see new leaves push out from the bud unions.

Patty S.