Your plant is one of the so-called thick stemmed begonias, they do not respond to the usual pruning of canes or shrubby begonias. However, if you have a few stems, you might experiment by cutting one stem back to soil level, new growth might appear there - it would give you an idea how to shape this sort of plant by cutting back occasionally. My thick stemmed begonia has very thick stems, larger than my thumb, occasionally the plant has been knocked over or dropped, the thick pieces break off easily, I learned if you just set them aside they will produce leaves all by their lonesome. This sort of violence keeps my plant in bounds. If your plant hasn't those fat stems, I guess you will wonder what I am talking about!

thank you woebegonia,for your info.did i understand you correctly that if a stem is broken off,and left alone it will grow new leaves?do i pot them in soil or what?thank you again

I'm not sure if your plant will behave as mine does since I'm not sure of the name of my begonia. The first time my plant had broken off stems I just set them aside, thinking I would toss them out. But a few days later (this was in the heat of summer, growing outdoors then ) I did a doubletake to see roots appearing on one and a bit of young green leaf appearing on the other, and near the base of the plant where the remainder of the stem was still growing, new growth started. However, the thick-stemmed begonias are not necesarily beauties, but they do have the reputation of handling heat very well, I had a friend in Oklahoma who tried to find only thick-stemmed begonias to grow for that reason.I don't know that you need to put a broken stem in potting soil,I think you might just set it
aside with a piece of plastic lightly on top, so it doesn't rot or even get too dry - Our environments are probably not similar and as an old friend used to remind me, Horticulture is not an exact science. . .

okay,thank you woebegonia,for he new info on growing the stems.i'll keep this in mind for the warmer months.thanks again,