I guess I goofed on an earier attempt to post an answer, but most tuberous types do stand a heavy pruning and a winter dormancy period induced by allowing them to get quite dry and then kept barely moist in a cool location indoors. Sometimes in warmer climates they can be left in the ground , provided it's not overly wet. I'd think however , just keeping them in a bright window in a warm indoor place might work as well, so you can appreciate them through the winter months , when it's gloomy, wet, and cold outdoors. I'm not sure about that specific variety though!

from page 192 of 'Begonias The Complete Reference Guide by Mildred L. Thompson and Edward J. Thompson'

"If temperatures are warm enough, semituberous begonias [of which b. boliviensis falls under] will not go into a period of dormancy as the tuberous begoinas do. Sometimes their growth will stop during the winter months and sometimes they will even lose their leaves, but they seldom will go into the complete dormancy. If they are grown under fluorescent lights with a temperature of 60º or more, their growing will be active throughout the year."

It also goes on to say that they will benefit from 40% humidity and frequent pinching and pruning so that they will then be bushy and compact.

So you should be able to enjoy your b. boliviensis throughout the gloomy winter of the Netherlands!

Good luck and post a photo so we can all see.
Lali

Is this cultivar of begonia evergreen? I'm looking for some shrubs for the curb that still have appeal in the winter.

I'd have to agree that B. boliviensis does not seem to need a traditional dormancy. I rooted about a dozen cuttings in October, and these young plants are blooming now in the greenhouse and under lights. I also stored a couple of tubers, but they look a little dessicated at this point, so I'll probably pot them and try to get them growing before April. This is one of the only tuberous varities that's been successful for me, given our hot, humid summer nights. One trick for this and all begonias seems to be to keep it on the dry side. This species is also reputed to be hardy when planted in the ground here in zone 7 (though it dies down over the winter), so I'll try that next fall. Motherearth, I'm not sure where you garden, but I'm guessing it might be evergreen in zone 9 and above.

I have one that got quite large last year. It spent the winter in the greenhouse, temp. set at 60. It dropped all of it's leaves and stems. It is now sprouting new leaves, so it looks like it goes through a dormant period, at least for me. I did not water it in winter, it just sat in the pot, which was 12 inches wide. I have quite a few begonias, and this is one of my favorites.
Darlene

I also kept a couple pots of these begonias in the greenhouse over winter (temp around 55) and they both went dormant. They are starting to shoot now. I had left them both in their pots over winter and did not water them.
Bubba - you say you rooted a dozen cuttings, how did you do it? I tried rooting in water and they just rotted. What was your process for getting them to root?

I took very firm stem cuttings in about September (some softer ones taken earlier in the season had rotted), made a mix of moist sand and perlite, made holes with a pencil and firmed each cutting in really tightly. My rule is that I have to be able to turn the pot upside down without the medium falling out for it to be right. Then I watered again, put the whole deal in a 2 gallon ziplock bag, put it under fluorescent lights in my garage and waited. I think it was about a month before the young plants were ready to separate. I think the tuberous species are harder to root, as a rule, perhaps because they have other ways of propagating themselves, but this one seems to work eithre way.

I don't do much rooting in water, other than when I go out the night before the first frost and collect dozens of coleus cuttings, and even those eventually go into some kind of soilless mix.