Contrary to the literature, I have not found post-Aug Nitrogen applications capable of stimulating new growth and even Aug applications only cause rank growth on branch tips- the rest of the tree seems to harden off in a manner unaffected by the late growth. I wish someone would do some research on this issue because I feel it is one of those things that gets repeated by academics without any specific research to back it up. Now, on your question, I agree with FN that there is no point in fertilizing now and also that it wouldn't hurt, might even help a tiny bit by getting some into the buds for a slightly quicker spring flush although I don't notice this affect on fall fertilizing of peaches. Probably just as well to wait until first growth in spring and then supply another application in early summer. With trees in potting soil it is easy for them to dry out when first transplanted and that could cause a quick change in leaf color- so it could just as well be too little water as too much. If finer soil around the coarse texture of potting soil is dry it will suck out any water from the potting soil by capillary pull drying it very quickly. At the same time, the coarser mix can't pull water from finer soil. This is a complication with planting potted trees. With peaches I find bare root trees tend to establish faster.

Here's what gets me about the rock powders, and I'll use Azomite as an example -- 89% of what you get with Azomite is silica, alumina, with calcium, magnesium and sodium in whatever salt forms they exist within the aluminosilicate that it is. The amount of other nutrients and "trace elements" in the mix is quite small, and as illustrated in another thread when they are applied as directed the dilution effect means even if they were readily available the amounts you are actually adding are likely to be very small relative to naturally occurring background levels. With more silicate rocks the availability will be further reduced. So unless someone can demonstrate a real, measurable effect from a well controlled study, spending money of rock powders as a means to "mineralize" soils seems to me to be a waste as well as most probably ineffective. All of that is before we consider all the things that can come along with some of the rocks deposits that we don't really want to reinforce in ag soils, and that are often in greater abundance in those rock powders/dusts than the ones we know to be beneficial. The good news is that for the same reasons that they don't make sense to me as meaningful ways to add micronutrients and trace elements, they probably aren't a threat either.

I was hoping someone else would answer you because I am not an expert, however, I will tell you what I think and hope it helps some. It is my experience that when the ground is cold, some plants, including citrus, have trouble absorbing iron. Also, if your water is very alkaline and your soil is also, then plants like citrus may need some acidity to help them with their iron absorption as well, especially if it is a young plant with a small and immature root system. If this were my plant, I would fertilize with citrus specific fertilizer (especially contatining iron) according to package directions, and then hand water this in with a bucket that has a teaspoon of vinegar per gallon of water applied. I would apply approximately 5 gallons of water at the base, a gallon or so at at time so that it can absorb slowly. Then I would wait a week or so to see if it helped green up the plant a bit, watching carefully for new growth as a sign of possible recovery. If it did help, I would hand water it again, minus the fertilizer, a week later. If the plant continues to recover, I would water as necessary with a hose, being cautious not to overwater, and once a month or so I would hand water with the vinegar solution. I am certain there are others with much more knowledge than I have, however, they have not responded and all I can do is tell you what I would do. I am in a warmer zone inland socal, but it has been really cold here as well, easily in the low thirties, and my trees are very green and fruiting well. Hope this helps . . .

I don't think the spots are anything to worry about. I have Hoyas that grow under many different circumstances and sometimes they get spots. You really only have to worry if you see mealies, scale, or if it's fungus, you'll likely see something either black or moldy. Now, is that obscura? If it is, the leaves look just a bit dehydrated. Mine hangs in full sun in my GH, and the leaves get like that when I wait too long to water. Other than that, I think they're fine. Denise in Omaha