Answer: Sometimes these trees will discolor somewhat during the winter due to cold and/or wind stress. There is no special fertilizer that would change this or improve the color, it is just a matter of time and being patient while they recover. Generally speaking you could use an annual top dressing of good quality compost and/or a general purpose or slow release fertilizer with an analysis of 10-10-10 or similar proportions. Read and carefully follow the label instructions.
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