Hello, in recent years I have become fascinated with hardy (in the UK at least) Begonias and have built up a bit of a collection. As some are a little bit difficult to get hold of sometimes I am reluctant to actually test them for hardiness until I manage to build up some spares. Some, such as Begonia grands are really easy to do this with as they form bulbils but many of the others e.g. pedatifida, taliensis don't and I was wondering if anyone had any easy tips on how to quickly build up stock so I can try them out for the winter and hand round to friends?