How are Blue Roses Made?
Mother Nature doesn’t make a lot of flowers in blue. There are some light blue shades (hydrangea, delphinium, etc) but most lean towards a shade of purple.
Flowers species, like people, have specific “genes” that make them what they are. Sadly, roses lack the specific gene that has the ability to produce “blue”. So, the blue roses of today are created with human intervention.
One way to achieve a blue rose is to include blue dye around the root system of the roses and/or harvest the stems from the plant and place them into water containing blue dye. The stem drinks the blue water causing the petals to turn blue.
Another option is to have the bloom of a white rose dusted with blue floral paint. (Non-toxic spray paint specifically created for flowers.)
Either option will achieve a rose that will have white/blue petals. Given that there is human or scientific intervention to create these rare beauties, it is likely that they will be more expensive.