Answer: Spring is a good time to repot, use a heavy container to counter the weight/height of the canes. Move it up a size as needed and then take care not to overwater after doing so. The cane types do not branch unless pinched, and some get really tall -- four feet or more in some cases. Here are general care instructions from the American Begonia Society you may find helpful. You might need to cut and paste the complete url into your browser to make it work correctly.
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