The New Blue Gladiolus
The gladiolus, like the rose and the poppy, seems to avoid the color blue. Mr. Burbank has succeeded, however, in bringing out the submerged hereditary factors for blueness that exist In this, as apparently in most other flowers. A long series of experiments in hybridizing and selection was necessary to produce this striking result.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 9 Chapter 6