A pink rose was immersed for 24 hours in a solution prepared by mixing 2 percent by weight of common salt with 100 mL of isopropanol. Then the treated rose was transferred to a solution prepared by mixing isopropanol, siloxane, methyl laurate, and methyl ethyl ketone in a ratio of 1:3:1:1 and adding 2 percent by weight of common salt thereto and was immersed therein for 24 hours. The rose was removed from the solution and air-dried for 24 hours.
The flower of the resultant pink rose was kept fresh for one year or more with the original pink color retained, and the branches were kept fresh for one year or more with the original green color retained.