Answer: The problem with your boxwood sounds more like a pest or disease than lack of fertilizer. But unfortunately based on your description, it's virtually impossible to make an accurate diagnosis.
If the plant in question was weaker than the others, the cause could be winter cold. Or it might be a disease such as volutella blight. If the problem is disease, remove the dying shrub and/or prune out and throw away infected twigs and branches. Rake up fallen leaves and throw them away too. (Don't add to compost.) Add fresh mulch.
Two good websites (Virginia Tech U.) that will provide additional background are:
But keep in mind that conditions in Ohio are different than Virginia.
Thanks very much and I hope this information helps.
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