storage of Begonia pollen
I am hoping to make a cross of B. sutherlandii (blooming now) with B. grandis (which will bloom in late August). Both have proven fairly hardy here, and I'm hoping to expand the color range and increase the size and hardiness of sutherlandii. My question concerns the possibility of storing pollen from sutherlandii until the female flowers of B. grandis are ready to receive it. Does anyone have experience with this? I've stored orchid pollen for several months to facilitate crossing plants which bloom at different times; I put it in film canisters with silica gel packs and keep it in the fridge. Any thoughts as to whether this might work for begonias?
Also - does anyone know if any of the semperflorens group have been hybridized successfully with either of the above species? I'm growing a reliably hardy white clone (Plant Delights is selling it as "Barbara Rogers", but I got it from my grandmother almost 30 years ago), and would like to do some work with that as well.
Also - in a report from the Chelsea flower show, Graham Rice highlights a new strain of B. sinensis which is supposedly larger in all parts than B. grandis. I have two clones of sinensis, pink and white, and each is a much smaller and more delicate plant than grandis. Any info on this? I know these plants are probably all subspecies of each other, so there's bound to be some variation, but I found the size difference interesting.