PURPOSE: To obtain a freshness preservative for cut flowers for making flowers admirable until the flowers completely come into full bloom almost without withering flowers even in the case of cut flowers.

CONSTITUTION: This freshness preservative for cut flowers is obtained by mixing a solution containing a guanidine salt compound and an alkali silicate metal with water and is used. For example, when the guanidine compound and sodium silicate are dissolved in water, sodium silicate is reacted with water and is changed into sodium silicate containing a large amount of oxygen. Sodium hydroxide is considered to arise in the process. The sodium hydroxide shows strong alkali and suppresses occurrence of bacteria. On the other hand, the guanidine compound directly prevents oxidation of methionine, extremely subdues biosynthesis of ethylene. Further sodium hydroxide is added and the guanidine compound is considered to prevent change of qualities of proteins and carbohydrates and amino acids constituting cut flowers with sodium hydroxide. Consequently, the freshness preservative for cut flowers capable of making flowers come into full bloom and admirable almost without withering cut flowers can be obtained.