Almost any cut flower can be dyed a different shade with only a few simple materials. Once considered the exclusive domain of goth culture or Halloween decorations, black roses are starting to show up as colour options in some ultra modern, avant-garde interior designs. Dyeing roses black is one of the easier DIY projects that you will encounter. Little more is needed than black dye, a vase, water and freshly cut roses. Not surprisingly, very dark red roses will absorb the black dye more quickly than lighter colours, but you can use any colour rose.
Fill a clean, flower vase with water.
Add black dye to the water. If you do not have black dye, try black ink. Add as much dye or ink as is necessary to turn the water almost opaque black.
Add plant food to the water and stir to dissolve it. The tiny packets of plant food that are usually included with roses purchased at a flower shop are fine.
Cut 1 to 2 inches off of the bottom of each stem at an angle under cool running water. Remove any leaves that are below the vase's water line.
Place the roses into the water. The stems will carry the dye to the blooms, gradually turning them black. The longer the flowers remain in the water, the darker they will become. It may take anywhere from a few hours to a couple of days for the roses to turn black, depending on the variety.
Some people believe that adding 1 to 2 tsp of sugar to the water will keep the roses fresh longer. Experiment to see if it helps.