1. Pick out a white rose (or another type of white flower). Use a craft knife to cut the stem at an angle, then split the stem into multiple sections (depending on how many colors you want).
2. Fill cups of water and mix in a few droplets of food coloring—one color per cup. More droplets will lead to a brighter color.
3. Use a rubber band to secure the cups together and place each stem section into a different cup of color. Allow the roses to sit for 24-48 hours.