In their habitat - they grow at altitude from 1500m and the temp between day and night so different (hot during the day and cold during the night, very cold in winter)
Just share some information related to habitat of this species so it can give you some more idea how to grow this species.
I have chance to see them grow in their habitat for many years, this species does not have a dormancy period like many species grow in other cold countries. C.subtropicum...
Last few months I also found Cypripedium lentiginosum in Vietnam and this is new record for Vietnam (just published end of October 2023).
So in Vietnam we just have 2 species in this genus and both are very difficult for cultivation and both of them are grow in the altitude from 1.600m above...
That is great, I have chance to see them growing in their habitat at some different locations so If you want to ask any more information a bout this species in their habitat, you can send me MS and I can provide as much as I could.