Answer: Raised planters are very difficult to plant because the roots are exposed to colder temperatures than they would experience if the plants were planted in the ground. The larger the planter, and the more sheltered its location, the better your chances of having anything survive. Mounding an insulating layer such as mulch around the planter can help; it is also important to make sure the plants are well watered during the fall. You might try dwarf Alberta spruce or some of the smaller junipers, but be aware that there is no garantee of survival.
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