[header] How to create blue roses [title] Gather the necessary materials. [step] To dye the petals through absorption, you will need powdered blue florist's dye, water, freshly cut white, scissors, dethorning tool (optional), a glass vase, and flower preservative (optional). Ideally, the roses will not have been soaked in or treated with water. 
Dry, freshly cut roses maximize the uptake of the floral dye. [substeps] Standard food coloring will also work, but you will get better results with a professional florist's dye.