Closed flowers fall off: pay attention to correct transport. Especially in winter, flowers are exposed to high temperature fluctuations.
In the cold, the vascular bundles in the stem contract, making water absorption more difficult. So-called “Blumenfrisch”, which is often included in bags with the cut flowers, can support flowering. Don't place flowers that have already opened next to those that are still closed. Similar to fruits and vegetables, these emit the gas ethylene, which affects the neighboring plants and causes them to wither.