Every November in the United Kingdom, and I believe Canada too, we sell small paper flowers in the form of poppies.
Some of the most devastating fighting of World War One took place in Flanders and Picardy, in the north of France. Afterwards, the only thing that grew on the site were red Poppies.
At Eleven AM, on the 11th day of the 11th Month (obv Nov) the First World War ended. The public wanted to commemorate the mass dead and so Poppies, symbolising the fields where so many died, were made and sold with the money going towards ex servicemen who needed financial support.

Now, every November, the Poppies are sold on the streets of the Uk with the money raised going towards people who were in the forces and need financial support, or their families who were dependant on them.
on 11th/11th and 11am there is a two minutes silence across the country and a national memorial service, led by the Queen (who has a FIERCE Poppy…look for pics) around the National monument to the World Wars (The Cenotaph) in London.

All Public figures – be them political, personalities etc -, aswell as the public, wear poppies when in public as a sign of respect and support.

Sorry to write so much… just a brief history/explanation of the Duchess’ one!