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From those altitudes, Cohan... pretty darn cold! This may be some help: http://www.chinaorbit.com/travel/china-weather.htmlhttp://www.backyardgardener.com/zone/china.htmlFrom the Chinese site, for example.....The diverse landscape of Yunnan makes it difficult to define a climate. Therefore it is easier to divide the country into climatic zones. In Yunnan you can recognize 3 kinds of climates, also called the “Three dimensional Climate”: temperate, sub-tropical and tropical changing over 4 regions: the low, hot river valleys, mountain areas and frigid highlands. The seasonal changes are small, but the changes in day-and-night temperature are in contrary much bigger.The average annual temperature is the lowest in the northwest, 7 degrees Celsius increasing more southward to 22 degrees Celsius on average in the Yuanjiang River Valley. Furthermore the rain-season start in May till October and it accounts for 83% of the abundant rainfall of 750mm-1750mm annually.
I have grown plants from up to 4400m altitude- no problems in winter under snow or with frost- the only problems are trying to persuade them that our summer heat is 'normal' for them Sometimes it depends on the species and on the whole I have more luck with plants from limestone areas- and presumably drier habitats, than I do ones from granitic areas. My soil is neutral and I add to it accordingly so I think that is not the problem.
It grows in extremely cold conditions when snow is possible even in august.