Hi Frank, i have used the Babel fish translator to try and find out how Ralfe had protected yunnanensis, But he does'nt mention it ,I would have thought though that he would have kept it frost free somehow.
The translation is'nt perfect but the pictures are exellent.
Translation result for http://pflanzen.plusboard.de/musa-yunnanense-bluete-gegen-musa-itinerans-yunnan-bluete-t4863.html