Fill a container, such as a vase or water pitcher, with a cup of water.
Add two to three drops of floral dye or food coloring. Continue adding a drop at a time to achieve the desired color. Dilute with water if it is too dark.
Snip a half inch from the bottom of the stem of your white rose on a slanted angle with a sharp knife or pair of scissors. This promotes adequate water absorption.
Place the white roses in the container for 24 to 48 hours, monitoring the roses during the color absorption process to achieve the desired color.
Remove the dyed roses from the container, snip the stems again and place the roses into a vase with fresh water.