I have had a tuberous begonia for a few years. I keep it outside in a spot where it gets some sun but is under a shady tree. I bring it in during the winter. It grows bigger each year and the leaves are full and healthy. It has never flowered. I have tried giving it more water or less water, more sun, less sun, fertilizer for flowering plants, tomato fertilizer, no fertilizer. What am I doing wrong?

Hi Denise. Your beautiful plant appears to be a Rex, rather than a tuberous begonia. Rex begonias are grown mainly for their attractive leaves; they do sometimes flower but that is secondary. The flowers are small and differ from those on a tuberous plant. Not sure of the variety you have but you can check out the begonia database here on NGA to see if you can find your particular variety.

I don't think it's Rex but rather a Rhizomatous Begonia. Here are some great culture tips.
www.bradsbegoniaworld.com/rhizome.htm

Yes Suzanne, I agree. That is what I meant to post; little brain blip.

Hey, it started with an R!

Thank you for your responses. Yes, the leaves are beautiful by themselves. I didn't realize it is not a flowering plant. I have heard that the tuberous begonia flowers are gorgeous.

It should eventually bloom, that link I gave says "Nearly all are seasonal bloomers that require a short day period to set blooms, so are late winter to spring blooming. Even though not grown for their flowers, they do put on a spectacular display of blooms during their short bloom season."

Yes, I did read that, however, I'm not sure what "a short day period" means and can't find information on what to do. Should I keep it in the dark? I have had this plant at least 2-3 years now and it has never bloomed.

I think it just means when the daylight is shorter, like winter months. Some I guess can be stingy with blooms. Try fertilizer as suggested.

I have a couple of similar plants, and mine live outdoors year 'round here. They bloom naturally in the spring for me. I wonder if it needs a seasonal change in temperature as well as differing day lengths to put on its blooms? It won't lose its leaves, but it might need a bit of a dormant period? It doesn't need to be kept in the dark to go dormant, as long as it has green leaves it needs light. It will stay green, but just not put on new growth.

When you bring it in for the winter, maybe you can find a particularly cool place (temperature-wise) for it, for the last few weeks before you put it outside? Do you have a room with a window that gets chilly at night? Or a spare bedroom where you could close the heat vent? Mine take temperatures down into the 40's quite happily, and then when the days start getting longer and it begins to warm up, they bloom for a few weeks.

It would help us to advise you if you could please fill in your profile to include your location?