Yesterday, the 5th day in the 5th month, was the day of the yearly boys' festival in Japan. Every festival has its flower, and the flower of boys' day is the proud blue Iris. With its sharp leaves it symbolizes strength and bravery, reminding of the edge of a Samurai sword.
It's not the season for Iris in Norwegian flower shops yet, but I found a picture from a couple of years ago of a classical ikebana arrangement using Iris as its main material. This is not a typical boys' day arrangement, but I think it shows the character of the Iris in a nice way.
Iris and Maple in a water and land arrangement.