Giving Blue Flowers

In the Wyrmsea Republic the gifting of blue flowers has become a tradition associated with warding off bad luck, thanks to an association between their colour and the value of the flowers.
The colour blue is associated with clear skies and calm seas, and is a popular colour in the Republic as a result, thanks to the nation being a naval power and heavily connected to the sea, both via the Wyrmsea waterfront to its north, and the Lock of Giants to the south, allowing Republic vessels to enter the Sea of Monsters. Flowers are not widely grown except in small personal gardens, thanks to the fact that most arable land is taken up either by food production or the carefully managed forests which produce the wood necessary for the Republic's shipbuilding programs. As a result of their scarcity, flowers are fairly valuable.
Blue flowers symbolised good weather, calm seas, and the regard that the giver of the flowers held for the recipient. Over time, this wish for the recipient to enjoy good weather came to represent a more general wish for good fortune to benefit the recipient of the flowers.
Although there is little spare arable land in the Wyrmsea republic, almost all the flowers grown for sale are now blue as a consequence of this. Almost every ship captain is gifted a blue flower before departure from the harbour, whether by their beloved, members of their crew, or from the mercantile guild that their ship is sailing on behalf of. A captain at the wheel of a departing ship without a blue flower in the buttonhole of their sailing jacket is considered a sign of ill fortune certain to befall the ship, and some superstitious sailors have demanded the ship turn around until one or more flowers can be secured. Flower-sellers are located at every harbour, and do a brisk trade in blue flowers because of this.