I am not sure if it's from being in a colder room or getting too dry, or combo of both, but these things aren't really amenable to winter @ my place except in the room that has the heat on the most often & where it's where I see every day to remind me to water. Then I get blooms over winter. So, I guess, try to keep more warm & not allowed to get really dry.
Strangely enough, in the few places I left leaves in the ground that I tried to propagate but thought nothing was happening & left them to become part of the mulch over winter, there were live little plants this spring. Could be worth trying @ your place with a few leaves, if it sounds like fun. You're also in Z8. ;) I had stuck the petioles about 2" into the soil probably around July but it's not much past that.
And keep the rhizomes above the soil, I've never tried to pot one by burying the rhizome.
It seems happy with me outside, but do you find that they fall apart in winter or that they're one of the less fickle Begonias? Any advice for indoor winter care? 
Those look familiar to the blooms that were on it when my Mom bought it. Is it different from beefstake?
I should have it moved to the right database entry. Would you be do kind as to point me in the right direction so I don't upload it incorrectly again?
