Yes, you can cut it and root it but I've found it doesn't root as readily as other cane begonias. I cut half a dozen stems of it late last fall and only one made it through winter in the basement. So as for timing I would say sooner is better than later so it puts roots down before winter. If you keep it in a warm spot then it should do just fine. You could also try it from seed you collect after it blooms and sets seed. I have dozens coming up from seed I collected last fall under lights now but it is a long way to a full sized plant.

Thanks, hc. I'm probably not motivated enough to try to grow out the seed. I'm thinking I'll pot the whole plant up this year and see if some of the other short canes put on height to even out the plant... then cut and (try to) root if I still need the shaping.

Do you have any cuttings you could sell or trade? Let me know please :)