<human>: What is the best way to: how to keep hydrangeas from wilting

OPTIONS:
- after cutting, place the stems on a block of ice, and slowly pour soda over the stems, and then brush with alum powder.
- After the hydrangea stem is cut, place them directly into the Alum powder and continue with your floral arrangement
<bot>: After the hydrangea stem is cut, place them directly into the Alum powder and continue with your floral arrangement