1. From the Hon. Archivist, Alleyn’s School, Dulwich, London, January 1994:
The cornflower is worn on Founder’s Day (the Saturday nearest 21st June being the anniversary of the day in 1619 when James I granted Letters Patent for the Foundation of God’s Gift to be created) by all members of Alleyn’s School and Dulwich College. On the following Saturday James Allen’s Girls’ School has its Founder’s Day and cornflowers are worn by them.
The cornflower was … the favourite flower [of Edward Alleyn] and is depicted in the reredos over the altar in the Foundation Chapel in Dulwich Village. The scene is the stable in Bethlehem with some additions – one of the wise men is Edward Alleyn, but there are also two extra ‘visitors’ to the Christ child. Two boys in the original school uniform. One holds a model of the Chapel, the other a bunch of cornflowers.
I was at Alleyn’s as a boy during (and just after) the last war. When the war memorial was unveiled on Founder’s Day we had to leave our cornflowers on tables in the corridor outside the hall. There was some story that the cornflower was a German national flower. I have never been able to substantiate this.
My records show that [the] cornflower tradition within the Alleyn Foundation started (probably) in June 1620 and has been carried on ever since. Thousands of the flowers are used by us every June. Three huge wreaths, each 2.5 feet across, are laid by the three schools on the Founder’s grave and over 6000 people are wearing them in Dulwich over the weekend (i.e. staff, pupils, former pupils and parents). I understand that it is impossible to buy cornflowers elsewhere in London then.

2. In France cornflower is the equivalent of the red poppy.  In the First World War the French army wore blue at the beginning of the conflict, therefore the cornflower is the symbol of remembrance.  I think poppies and cornflowers grew together on the side of wheat fields [South London Botanical Institute, July 2020].

Images: main, cultivated, Norwood Road, West Norwood, London Borough of Lambeth, July 2014; upper inset, cultivated, The Collector Earl’s Garden, Arundel Castle, West Sussex, June 2017; lower inset, cornflowers on Edward Alleyn’s tunic, on the 2008 statue of him, Dulwich, London Borough of Southwark, December 2020.