The poppy was taken as a symbol of remembrance as it flowered through the muddy carnage in Flanders through the First World War. You can find out more here http://www.greatwar.co.uk/article/remembrance-poppy.htm

The choice of poppy was also inspired by the poem “in Flanders Fields” by John McCrae

In Flanders fields the poppies blow
Between the crosses, row on row,
That mark our place; and in the sky
The larks, still bravely singing, fly
Scarce heard amid the guns below.

We are the Dead. Short days ago
We lived, felt dawn, saw sunset glow,
Loved and were loved, and now we lie
In Flanders fields.

Take up our quarrel with the foe:
To you from failing hands we throw
The torch; be yours to hold it high.
If ye break faith with us who die
We shall not sleep, though poppies grow
In Flanders fields.

See my other more realistic poppy video here