i dont know the term 'cane' begonia???

is it tuberous?? .... if so ... why didnt you let it go dormant in fall ...

presuming its not.. then i know why you enjoyed it indoors during winter ...

isnt that a young sprout down there?? ... if so.. i dont know why you cant cut back the old trunk ...

i would wonder.. if its not tuberous.. why you cant root some new growth tips ... many of the Bs are easily rooted?? .. start some new young plants.. and be done with this old one??? ... often.. its just not worth.. trying to reinvigorate the old plant.. and much easier to start some fresh new ones ... [part of that equation might be that the old media is wearing out.. in the pot.... and again... before i tried to repot it.. i would try to propagate it]

ken

In my opinion this is not a cane begonia. To me it looks like an etiolated wax begonia, Begonia semperflorens cultivar. You can cut them back if you think it's worth the wait for regrowth. Maybe do one stem at a time. But I agree with hc mcdole that it's easier to start again. Whatever you decide, give the plant the light it needs. Otherwise it'll just stretch up again.

I have 2 pots like this that I rescued from the curb 2 autumns ago. I have found that snapping off the cane about halfway often induces them to send out new leaves, and the snapped off pieces root easily in the flower beds. So far this has worked to refresh the plants after overwintering and given me more color between the perennials.

Raee, are yours a cane begonia species or wax begonias?

The photo shows a wax begonia (semperflorens). There are many hybrids today with the most popular being "Big". Yeah strange name but that is what it is.

It is not a tuberous or a cane. A cane is a taller grower type begonia (like a bamboo cane) with longer sections between nodes. Canes can be dwarf so perhaps 12 inches tall to giants over 6 to 8 feet tall and taller.

This is Begonia 'Big; and a tuberous in the middle of two from last year.

And in 2017, a saved BIG begonia but it was not as spectacular as one bought in spring.

Dragon Wings, Big, and Kong Coleus occupy the same pot two years ago.

Best to treat them all as annuals unless you feel like playing with them.

a sideview might show a better idea on the growth possible

I couldn't find any dragon wings this year. Hard to believe. DW on the left, Big on the right.

They were good bedding plants too.

floral_uk, I really don't know. They are the type that is commonly sold here in hanging baskets, but are not the beautiful tuberous types. Mine look just like the one in linnea56's photo.

So, that would be a Wax Begonia, B semperflorens.

Thank you all. Those did so well last year, that I wanted more of them. I had hoped for 6. But the distant nursery where I bought them only had a couple of plants. The bronze leaves go really well with my pot color scheme. Plus they did great in the hot sun of my front patio. Blooming machines.

Ken, I usually dump half the old media at least into the flower beds. Then replant any saves plus new plants into fresh media. I DO let my tuberous ones go dormant then store them pot and all in my basement crawl space. I lose some but most come back. I pretty much know what works for me with tuberous but not with this other type.

Raee, I'll give that a try. The bases I'll pot up in small pots and if they do well, I'll be ready to refresh one of the planters by the time other stuff like petunias die away.

I wish I had your touch for tuberous. I have no luck with those - at best I'll get a little sprout that dies.

raee, you mean keeping tuberous over? That took a lot of experimentation.