Watch this video from USAA about the Buddy Poppy. The buddy poppy was named in 1923 by the VFW. Its origin came from the Great War, WWI, and the red poppy that flourished in 1915 at the battlefields of Belgium, France and Gallipoli.
Because of this, the red poppy became the symbol of remembrance.
History of the Buddy Poppy
From a website on the Great War, WWI