Decoration Day, renamed Memorial Day beginning in 1882, was first celebrated in the United States following the Civil War; it commemorates U.S. men and women who died while in the military. One of the most famous parts of Memorial Day, however, arose during World War One.
The practice of red poppies on Memorial Day originated in 1918 with Moina Michael, who was inspired by Canadian John McCrae’s famous poem, “In Flanders Fields” (1915). The tradition spread from the United States to France via Anne Guerin, who poineered the selling of poppies, real or facsimile, as a way to raise money for various causes to benefit veterans and the victims of war. Through her advocacy, the sale of poppies for charitable causes spread to The United Kingdom, Canada, New Zealand and Australia.
White poppies are sometimes worn in this context, and symbolize looking forward to peace, rather than back at sacrifice.