Care of Begonia

Hi BBB: Begonia pendula is one of the tuberous ones, so usual procedure is to bring the plant to a cool room or shed at end of summer to let it die down, stop watering, then keep in sand/compost mix overwinter and restart them into growth the following early spring, inside, or outside in their flowering positions, though this will mean later flowering. I'm sure you know all this already though - if you're asking how to keep it as a plant all winter, you'll have to treat it as a houseplant.