Which poinsettia color is the rarest?

Answer 1

Blue is the rarest color for poinsettias (Euphorbia pulcherrima).

Specifically, red, pink and white and marbled or mosaic combinations of those color as red and white or pink and white on each bract (modified leaf) are the most common. White is the color when carotenoid pigments take over the developmental process previously dominated by the green color-producing chlorophylls. Pink requires the efforts of carotenoids and anthocyanins. Red, purple and blue reflect the dominance of anthocyanins. But blue is the rarest outcome of that anthocyanin dominance.