Junipers can be kept indoors when required. I do this nearly every year. I get a gift cert to the local bonsai shop for x-mas. I go to the shop and the only interesting trees are junipers. They have gone dormant for a couple months then he brings them in for the holidays. Durring my time off over the holiday break I style and re-pot

. I grow them in my basement in humidity trays under regular old cool white 4 foot shop lights kept 1-2 inches from the top of the tree. I do mist the trees once a day. The temps are around 60-70F.
Once the temps get above freezing they go outside and stay outside from then on out. I normally winter in the back of my garage from then on.
So it is not optimal but can be done. The penjing pic below was started this way 2 or 3 years ago. And the other one was done this year.
Newt
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Connection with gardens, even small ones, even potted plants, can become windows to the inner life. The simple act of stopping and looking at the beauty around us can be prayer. -Patricia R. Barrett