I heard that Cyclamen hederifolium also tolerates humid continental climate better than other species and thus capable of growing in Korea, though they usually get their flowers zapped by frost. I wonder if that's the case in Japan too....

I feel East Asian summer monsoon is truly a big obstacle when it comes to raising bulbs and border perrenials. Its so hard to find flowers that would withstand two months of rain unscathed, though plants from Eastern North American region tend to grow better.