Answer: The purple could actually be a normal occurrence in that some varieties of juniper do take on a purplish or coppery coloring in the winter. This might be more pronounced in a sunny location than in a shady one. You might take a look around and see if similar textured/shaped juniper plants in your area are also coloring up for the season now. If you still have doubts, you might take a photo and consult with your county extension or experienced, professionally trained nursery staff for another opinion.
As an aside, I would caution against over watering them since we have had rain now. The soil needs to be kept slightly moist but never soaking sopping wet since junipers are subject to root rot if kept too wet. Once the soil freezes of course you do not need to water at all.
Good luck with your junipers.
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