My Irene has just started blooming and the flowers are going to be huge, however, mine is much taller than yours with a couple of strong stems ( a wonderful gift from a begonia friend). Even though that is the case, I almost slipped a stake in the pot today to support it. I am concerned that a rain (if we ever have any) may bend even my much thicker stem. I would support however you can and protect it from heavy rains. Even so, it is hard to find fault with such a beautiful begonia!
Thanks, I will do that, it was such a gorgeous plant, that is a 10" pot it is in. We haven't had any rain in (too) many weeks but the humidity has been terrible because it is raining all around us. I think the plants feel like I do, we are all getting the vapors.
I'l be sure to stake it this morning, that would show off those flowers better also. Thanks again.