The cornflower is the chosen flower of the Austrian Freedom Party, even though it was once associated with the Nazis.
It was the German Kaiser Wilhelm's favourite flower, and was used by pan-German nationalists in the 19th Century. Between 1934 and 1938, when the Nazi Party was banned in Austria, it was the secret symbol Nazis used to wear in order to recognise each other.
It's traditional for Austrian MPs to wear a flower in their buttonholes at the opening of parliament. As the colour of the Freedom Party is blue, they wear a cornflower - but have been criticised for this.
In the past, Hofer has said he wants nothing to do with the Nazis, but refuses to let them take away things like the cornflower. However, ahead of the vote on Sunday he's now told the newspaper Die Presse that he's asked his friends within the FPÖ to refrain from wearing the flower so that they won't have to keep defending their choice.
On Monday, Hofer tried to appeal to female voters by posting a picture of a bunch of flowers on his Facebook page, with the words: “Respect for every woman who manages to build a family, raise children, and at the same time build a career.” He added that he also has “the utmost respect” for mothers who decide to stay at home and care for their children. In the first round of the presidential election in May only 40 percent of women voted for Hofer - and 60 percent for his rival, the Greens-backed Alexander Van der Bellen.
Van der Bellen narrowly beat Hofer in May, but the FPÖ got the result overturned over procedural errors. A re-run set for October was again postponed because of faulty postal vote envelopes.
Like other populist groups in Europe, the FPÖ has won support by stoking concerns about immigration and what it portrays as an out-of-touch elite.