Not sure if this is what you are looking for or not; here is some info.
If you dip the ends of cut flowers in alum and then put them in water, they will draw up more water into the stems.
Hi, you can put some of the powder in a little bowl and dip the end of the stem into it. It will help your flowers stay fresh a little longer.
Here's some more info! https://ubloom.com/blog/2017/05/18/hydrangeas-alum-whats/
Hi Trm: Are you trying to root your flower or just keep them for an arrangement. If you are trying to root them, use a product called Root Tone. If for an arrangement, take a pitcher of water to the garden and drop bloom stems into water immediately after cutting them (important). As you arrange the blooms, recut the stems and dip the bottom 1/2 inch of stem into powdered alum. Arrange as usual in water. (I know this washes off the alum, but it works!) Good luck
Cut Flowers On Your Table | The Secret To Long-Lasting Bouquets
Betsy spelled it out beautifully!
Why thank you Maura, you're making me blush :)
Perhaps this will help: https://plantaddicts.com/cut-hydrangea-care/
Betsy brought awesome idea !
Agnes, you are making me blush, too :) Thank you.
Hydrangeas love that!
Here's a post that might help - https://www.whitelacecottage.com/2016/09/how-to-extend-the-life-of-cut-flowers/
I would love to find out more about that too so I am following your question
Dip fresh hydrangea stems in alum to make them last longer.
Hello Trm12758390, use alum to help preserve your fresh cut stems, Take a pitcher of water to the garden and drop bloom stems into water immediately after cutting them (important). As you arrange the blooms, re-cut the stems and dip the bottom 1/2 inch of stem into powdered alum. Arrange as usual in water. (I know this washes off the alum, but it works!) hope this helps you out.