Rodgers & Hammerstein’s The Sound of Music is full of great music from beginning to end.  Edelweiss is one of those memorable tunes. It is sung two times in the movie. The first is at home when Captain Trapp sings it to his family and his oldest daughter joins in. The second time is at the auditorium before his fellow Austrians. Then of course the flight from the Germans begins. The musical and the film took great liberties with the Trapp family story (changing genders of the oldest children,compacting the story and changing other general details).

In reality the family was already a well known singing group prior to the German annexation of Austria (this was due in part to the financial loss Von Trapp suffered when a local bank collapsed). Trapp, who had earned the noble title of baron for his daring exploits as a submarine commander in World War I,was indeed going to be called to active service in the German Navy. His two oldest boys were likely to be compelled to join the German military as well. They could see the effects of the German takeover and what it was doing to Austria. Friends disappearing, the German Nazi ideology being implemented everywhere. So they choose to leave but, unlike the movie, did not walk over a mountain. Thanks to his being born in an area that was ceded to Italy after World War I, he had Italian citizenship. So did his family. They put on day packs and took the train to Italy leaving everything behind.

They would eventually make their way to America. And they would start a new life as traveling singers criss-crossing the country by bus and singing folk songs from around the world living as frugally as possible. Their Christmas music was also highly regarded. They would settle in Vermont as their home base. Eventually it would become a lodge which still exists today (and owned by third and fourth generation descendants). The two oldest boys did join an army, the U.S Army, and at the end of the war returned to see their old home in Salzburg. It was still there but Heinrich Himmler had lived in it! The house would be given to the Catholic Church and still stands to this day. The lack of basic supplies for Austrians after the war was appalling. So Captain Trapp (he dropped the von from his name by this time)and Maria founded a relief effort to send needed supplies to fellow Austrians. The Trapp family name has a certain honor in Austria though not because of the musical, but because of his relief efforts and his refusal to serve the Nazi war machine.

Update(31 May 2016)
*It is sometimes thought the song Edelweiss is akin to an Austrian national anthem. However it was written specifically for the play. And for a particular actor Theodore Bikel.
*The Austrian national anthem is called Land der Berge, Land am Strome (Land of mountains, land by the river). Prior to the forced annexation of Austria by Germany, the anthem was Sei gesegnet ohne Ende (Be Blessed Without End)when it was Austria-Hungary. During the Nazi period, the German anthem Deutschlandlied (often mislabeled as Deutschland über alles)was the official anthem. After the war and to avoid any further connections with Nazi Germany or the old Austria-Hungarian Empire, the current anthem was selected.
*Edelweiss(Leontopodium alpinum)is a mountain flower generally found between 5,900–9,800 ft in Germany, Austria and Switzerland. It generally blooms in the early to mid summer but is short lived plant. Many people grown it at home because of its beauty either in containers or in gardens. The plant itself is non-toxic and has been used for herbal remedies. Better still is that deer will not eat it and is drought resistant. However it does require a mild to cool climate in order to thrive.