Hans,
Goodluck!!! I must say that I saw the plant in Vietnam recently, but all the seed had dropped by the end of October when I was there. It is very high elevation where it occurs and is in very cool forests, even in China. My native amplexifolius and lanceolatus (roseus) occur only a 1.5 hour drive, but I could not grow them because they are 1500m up in the mountains.
Aaron