To prune a juniper bonsai, it is recommended to do so during the early spring or summer when the tree is actively growing. This allows for easier maintenance of the desired shape. Pinching should be avoided.
Juniper bonsai trees can be kept outdoors and tolerate winter temperatures above -10 degrees Celsius. If temperatures drop lower, they should be moved to a cold indoor space or protected by a bonsai cold frame or garage.
Improper watering may cause needles on a Japanese Juniper Bonsai to turn brown. Junipers do not need to be watered daily. The presence of a layer of rocks glued to the soil cover can impede proper drainage. Too much sunlight can cause junipers to turn yellow. If more than one branch is brown, the bonsai may be dead.
Repotting of Juniper bonsai trees should only be carried out during their dormant season, which is usually in winter. The optimal time for repotting is in late winter or early spring to achieve the best results.