The poppy's significance to Remembrance Day is a result of Canadian military physician John McCrae's poem "In Flanders Fields". The poppy emblem was chosen because of the poppies that bloomed across some of the worst battlefields of Flanders in World War I, their red colour an appropriate symbol for the bloodshed of trench warfare.

At eleven this morning, we will be observing a moment of silence and remembrance for all those who have been to war, those who are at war now and those who will have to go to war sometime in the future. Thank you all.
IN FLANDERS FIELDS
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.
— Lt.-Col. John McCrae (1872 - 1918)