The Juniper Tree needs to be dormant in the wintertime, so please put it in an unheated garage so as to protect it from wind, and you can only put the Juniper on display for about 3 days before returning it to the garage. Even in the winter, however, it needs water. Place snow on the soil to water it periodically, as often as possible.
Alternatively, if you don't have an outdoor sheltering environment, you can place it indoors only if you simulate a constant ideal setting. We have experimentally and successfully kept our juniper bonsai trees indoors where they have been thriving for years. By using artificial lighting as well as increasing the humidity of the plant’s surrounding environment. A good way to achieve this environment is by keeping your plant in a glass receptacle-such as a fish tank or terrarium-with the light directly focused on the plant.