It is traditional to wear a red rose on St. George’s Day, although it is difficult to establish why or when the tradition started.
Some suggest the red rose was adopted as England’s national flower after King Edward III (red rose) defeated the House of York (white rose) during the Wars of the Roses. But it was Edward III who created the Tudor Rose (a mix of red and white rose petals) as a symbolic gesture of unity, so it seems unlikely he would have promoted red over white.
We share the custom with many other countries, including Catalonia in Spain. Every April 23rd on the day of Sant Jordi, or St George, men give their love a rose, while she in return gives him a book.