Hello, felt I had to write. First let me tell you a little bit about myself. My wife and I grow terrarium begonias, show in the ABS convention shows, and also local/State, and other Begonia shows around the U.S.
I am a certified judge for the ABS, and my wife and I also gave a seminar at the recent ABS National Convention in West Palm Beach Florida. Between the two of us we have over 45 years growing experience where Begonias are concerned.
There has been much debate about B. bipinnatifida. But I can assure you that it is strictly a terrarium begonia. That is to say that it requires very high humidity, low temps, and moderate light.
You will get people telling you that it will survive outside of a terrarium. However, it will not. The only place it will survive is in a terrarium(high humidity enviroment). Greenhouses would fill the bill, as they are just big terrariums, if you stop to think about it.
You can presently find them in retail greenhouses, where the workers might innocently tell you that they will live in a household enviroment. This is what they have been told by the wholesale suppliers. However, if you want to try to grow it in your home, please try it. Then if you want to try it again, try it in a terrarium. Watch the moisture as it likes to be damp and not wet.