I agree, cane begonias are fun -they are so easy to root. The 'How to root cane begonias', on Brads Begonia World, was fascinating reading to me. But I can't find it anymore. Did Brad pass away and the site abandoned?
Anyway, he illustrated how you should have a couple nodes below soil and they would send up new canes.
I have/had a few big canes and a few medium or smaller ones. I have problems at times, but when they are happy they are amazing.
