My roommates mom gave me this orange tree but I wasn't ready to plant it because I will probably move within a year and I want to keep the plant. So I put it in a pot with citrus fertilizer, also some regular fertilizer on the top because it didn't fill as far as it needed to. The leaves started curling in the last few days and turning brown. The branches were green, last night so I wasn't as concerned but now they are turning brown too. I live in Phoenix and there have been a few freezing nights but that was before I potted and the tree was ok, up to that point, though perhaps I am too novice to notice. I think I might have over watered it after potting but I haven't watered it since Monday though it did rain Tuesday it is under a hanging so it shouldn't have gotten to wet. The soil is still wet from that though I'm not sure if it's wet all the way through. I feel really bad for the little guy can I save?
Welcome to the forum. If the tree was damaged by exposure to cold temperatures, the leaves would be dried but would remain green. If the tree had been over-watered and thus afflicted by root rot, the leaves and young growth would have withered; there's no sign of that. Therefore, given the three possibilities you've listed I would suspect this has something to do with the fertilizers. Perhaps the amount was excessive. The mottling of the leaves looks suspicious. Have a look at the section titled 'Biuret Toxicity' in the following document: HS-797/CH142: A Guide to Citrus Nutritional Deficiency and Toxicity Identification. Did the leaves look anything like those in the photo at some point? Whatever the cause it may be too late to do anything about it as there is considerable damage. You may have a chance to save it if the main stem is still alive. Is it still green above the graft line or has it turned brown as well? If you think there's still life left in it and that the tree is worth saving then I suggest you replant it in completely new soil without any fertilizer.
Thank you so much I will try to save it. There is still green above the graft and even a few leaves that are still green. Now that it is morning the branches look more yellow than brown but should I cut them back?
I took a picture of the roots. Do they look ok? Should I do anything for them? Let them dry a little?
The roots look okay. I would prune away the part of the stem that is obviously dead or dying; what remains should be healthy looking, with green under the bark. Remember to reduce watering to commensurate with the loss of leaves.
