I'm not sure what we are talking about here. Is the plant one of the B. dregei types which will form a caudex with age?I have never heard it referred to as being 'succulent' although there are a few others considered that way. My usual survival hope is to enclose a plant in a tight zip bag and put it in a cool place, and see what develops.I don't know of any definite dormant period for the B. dregei types.

I'm assuming it's some B. dregei hybrid. It looks like pictures of B. partita, but that might be a variety of dregei. It was... labelled as something I can't actually find pictures of.

I was under the impression it was succulent given the caudex and South African origin.

You could try posting this on the cacti and succulent forum. There are folks there who have these "succulent" begonias. They will hope for a pic, I bet.

Amccour..Could your Begonia be Richardsiana? They grow a caudex, but the caudex takes a couple years, 'from seedling' to show before it thickens.

Or B. Tripartita? This Begonia grows bulblets.

If the stem you want to root is woody, brown inside, it probably won't root.

The first thing I'd have done is filled up the sink w/water, let Begonia soak about 15 mins or until soil was fully saturated. After placed in a cooler, shady position.

How's your Begonia doing now? Toni