Enzyme activity for oxidation are tannins. The nature and intensity of browning varies from species to species.
Research is currently underway for additional control measures.
The leaves can also be dried. Smaller varieties may benefit from hanging upside down, while large blossoms with dry straight up in a container. Keep flowers in a dry, well-ventilated place for 2 weeks or until completely dried. Once dry, the stems remain rigid for use in dry foam or dry containers. Recut stems of fresh flowers and place in a solution of one part glycerine to 3 parts water.