https://www.bhg.com/gardening/flowers/facts-about-dahlias/
5. There are no blue dahlias
Dahlia flowers come in every color but blue. In the nineteenth century, a London newspaper offered £1 to the first breeder to create a blue dahlia—the reward has never been claimed, but there have been many attempts that are near-blue, but not a true blue flower. Like many flower varieties, there is also no pure black variety—only dark red and dark purple.


