Well, I have grown it from seeds collected in Mongolia. The seeds may take two winters before they germinate. It does well and has nice flowers even in a much warmer climate in Germany. In Mongolia it hardly grows over a foot high. And my German plants are not much higher. Thus I am not sure if the Mongolian/Siberian rosa acicularis is really the same as the American variety. There is also some confusion with rosa davurica. I am in Mongolia frequently and today I have checked again the pine-larch-birch forests at 2000-2500m altitude.Plenty of rosa acicularis here. Nice colouring of the leaves and nice hips. Morning temperatures at the moment around freezing, though today was exceptionally cold. Seems to grow everywhere in undergrowth under the pine trees. Doesn't like so much dry meadows. Pressure from other shrubs or trees does no harm. In winter temperature drops to minus 40 degrees Celsius and below regularly.
http://greif.uni-greifswald.de/floragreif/taxon/?flora_search=Taxon&action=species&gen=Rosa