Its interesting you did not mention any citrus. Citrus has its problems but overall they are easier to grow and require less toxic sprays for the most part. Fruit trees don't take a lot of physical labor but they do take a lot of brain time to make sure you are on top of the Insects and fungus that want to prevent you from having fresh fruit. It is all about timing and knowing what to do when. Peach trees in our hot humid weather have to be sprayed. If you have gray squirrels, then you must protect the peach tree or they will eat them all. Still, fresh peaches are hard to beat. Call your local Extension agent they can be a great source of information. Here is a link that might be useful: Georgia Home Orchard

Again, check the soil way down at the bottom, Mile High. You made up your own mixture, and believe it or not, it may still be retaining too much water at the bottom of your pot. Cactus mix and perlite will still retain too much water. Especially when you bring your tree inside for the winter. Which is why Mike shared with you using the 511 mix. O don't even use cactus mix and perlite in S. California, where it is almost as dry as Colorado, and I can keep my trees outside all year. My customized 511 mix is 3 parts bagged mix (usually MiracleGro Vegetable Soil), 1 part perlite and 1 part small bark chips (usually reptile mix or coarse orchid mix). I think the issue you're having is from past and possibly continued root damage, some of it a delayed response, and possibly some of it a response to continued root damage. I think the roots are damaged enough that the plant cannot sustain growth at the apical ends of the branches, and they are just dying back (called Die Back, interestingly enough). So, I would make absolutely sure you're not continuing with more root rot. I think the chlorosis you're seeing being caused by inadequate root growth, not inadequate fertilizer. If the roots are so damaged that they cannot take up nutrients, you'll see chlorosis, despite fertilizing. Your best bet? Re-pot now, with 511 mix. Trim off any dead, rotten roots. You may even have to flush the pot with a weak bleach solution to stop the root rot (I think Mike has had to do this in the past, so search the forum for the bleach to water ratio, you don't want it to be too strong, or you'll kill your plant). Then, once re-planted with a properly porous mix, start fertilizing with 1/2 strength Foliage Pro until you start to see some recovery. Once you do, you can move up to full strength Foliage Pro, and add some Osmocote Plus time release fertilizer (please do not use anything else, many of the time release fertilizers have too much urea--based nitrogen, which will burn the roots, and also do not contain micronutrients, as Osmocote Plus does). Patty S.

Sometimes the rootstock takes over a tree that was grafted and abandoned. This can leave you with weird inedible fruit. Or it could be lacking nutrients, making the fruit bad. Even if the fruit isn't good, it could still be a beautiful tree! It could use some pruning and trunk reinforcement. Try a bungee pulling it the opposite way tied to a sturdy stake. http://homeguides.sfgate.com/tell-citrus-tree-gone-wild-38266.html

You're in the wrong forum as this is Landscape Design. Return to the master list of GardenWeb forums and choose another that is about growing plants. It might be trees, shrubs, or a regional geographic forum where citrus is grown. I don't know if there's a forum for citrus proper.