There are limits to the color range of flowers, which can be achieved using traditional breeding techniques. Blue pigments, for instance, are lacking from many plants. For a flower to be blue it must contain the pigment delphinidin, and to have this pigment, plants needs to contain the blue gene. This pigment is found in the vacuole of the flower cells, and the pH in the vacuole determines how blue the pigment appears. Traditional carnations couldn’t produce the blue pigment, delphinidin, and it was not possible to breed blue carnations through traditional means. Although there have been blue carnations available since the 1970s, but their blue was due to food color, not natural pigments. Carnations do not naturally produce the pigment delphinidin, thus a blue carnation cannot occur by natural selection or be created by traditional plant breeding. It shares this characteristic with other widely sold flowers like roses, lillies, chrysanthemums and gerberas.