BIOPON Blue Hydrangea Coloring Fertilizer 200g An easy-to-use and fast-acting hydrangea coloring fertilizer. It penetrates the structure of the plant, staining its flowers blue. It ensures an even distribution of color, maintaining the effect of color change for a long time. COMPOSITION: NITROGEN 7%, POTASSIUM 12.5%, MAGNESIUM 2%, SULPHUR 46%.