The freshness test: How you can tell when buying that cut flowers last a long time. If the heads hang a little after purchase, place the bouquet in a cool place for a few hours, wrapped tightly in paper in a vase with cold water.
A strong stem is important for large flowers. Once in the vase, the flowers that have been cut again should be given fresh water every day and should be supplied with a nutrient-rich and bacteria-inhibiting freshness agent.