My sister called me some time last year and asked if I knew a way to keep Hydrangeas from wilting in a vase. My first thought was that, if I did, I'd pick more Hydrangeas. But I must have told her about this method some time in the past and forgotten it. (After all, I have to make room for all the new stuff that enters my brain.)
So I found it! The method is simply this:
1. get some Alum
2. put about 1/4" of the Alum powder into a shot glass
3. cut the Hydrangea stem and dip the end of the stem in water.
4. dip the wet, newly cut end of said stem into the Alum powder.
5. tap off the excess powder.
6. put the Hydrangea into a clean vase of fresh water.
Five days later, the stem is almost a snappy as a fresh green bean.