PURPOSE: To quickly produce a long-lasting flower by coloring a natural flower and causing the flower to open by buoyancy of water.

CONSTITUTION: In a method for producing a flower of a natural herbaceous flower, a fresh natural herbaceous flower is colored by an oil base water insoluble-solvent coloring agent. After coloring, the fresh flower is put in hot water to soften the flower. A weight is affixed to the stem of the softened flower. The flower is then put in hot water in a transparent container so that the flower opens by buoyancy. An antiseptic agent and an acidic material are added so that the flower can last for long-time appreciation. In this method, after the flower is softened, the flower is placed in cold water to provide the petals with a shape, thereby adjusting the extent to which the flower opens in water.