Answer: Unfortunately, calla lilies and begonia are not winter hardy so they will not do in this case. Perennials are sometimes difficult to overwinter in pots, even if they are winter hardy, because you still need to insulate their roots. Using larger pots such as half barrels, or moving the pots to an unheated garage, or piling mulch around them or sinking the pot in the ground for the winter or even packing it in a styrofoam cooler along with dried leaves or straw are all methods of trying to insulate the roots. Most perennials bloom for just a few weeks each year, so you'll want a variety of plants. Some to consider would be dianthus, daylilies (look for reblooming varieties), yarrow, cosmos, purple coneflower, and sedums. Unfortunately, most perennials have too large a root system for the typical hanging basket, but you might try some of the herbs such as thyme or oregano or possibly the tiny strawberry varieties such as "Pink Panda".
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