Answer: Your Blue Atlas Cedar tree needs to be planted outdoors as soon as possible. It will not thrive indoors, and keeping it indoors will prevent it from adapting to the seasonal change on its normal schedule -- it needs to undergo a gradual seasonal change outdoors to prepare for the winter cold.
It needs a location with well drained soil and full direct sun all day long. (In most cases a spot where rhododendrons are growing would not be sunny enough for this tree.) In your area it would also do better in a sheltered spot with protection from sweeping winter winds. Apply a generous layer of mulch in a flat layer spread out over the root zone in late fall, but do not allow it to touch the trunk of the tree.
I am a little concerned about winter hardiness. This tree is generally considered winter hardy into zone 6. Your zip code places you in the warmer part of zone 5. If you have a sheltered microclimate, then it may be fine. But keeping it indoors is not really an option -- it needs some winter chilling.
The other issue is size. This is potentially a very large tree over time, up to about 60 feet tall, so you need to plant it somewhere with space for it to grow and mature. Repeated pruning to keep it smaller will ruin the natural shape of the tree. Here is more information about this tree you may find helpful.
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