Found this on the Hidden Springs Peony Farm
https://www.hiddenspringspeony...
How to save peony blooms
Long story short, you'll wrap your stems in plastic and lay them in the fridge until you fancy a bit of beauty.
This is such a great idea when you know you'll have company in mid-summer or perhaps a wedding. Or maybe you're just celebrating a summer day.
No matter the reason, you can enjoy a vase of peonies well after spring has passed. Here's how.
Cut your peony BEFORE the flower opens. For a large double peony, the perfect time is when the bud feels like a marshmallow and is about the size of a golf ball. A single, Japanese or Anemone form peony will be much smaller and should be cut when it is firmer. For these forms, cut the stem when the bud starts to show color. There can be a little bit of experimentation here to get it just right. Picking it too early and it may never open. Too late and it will open in the refrigerator. Practice makes perfect.
Remove all the leaves from the stem.
You'll want to store your peony stems in plastic. Refrigerators can provide good temperature control for the flowers but they are quite dry inside. Wrapping the buds in plastic will help them retain moisture and not dry out while they await the vase. Produce bags, plastic grocery bags and even large resealable baggies work well. You can wrap them individually or in small bouquets. If the entire stem doesn't fit in the bag the ends can stick out without protection.
Lay the wrapped stems on a shelf in the fridge. You can stack them up on top of each other to save space.
Check on the stems periodically and remove any that show signs of mold.
When you are ready to take the flowers out and enjoy them:
Give them stems a fresh cut off the bottom. The flowers will have dehydrated during their refrigeration and may be a little wilted. Don't worry.
Place the stems in a vase with lukewarm water and flower food. A cool room is best. Avoid direct sunlight. The blooms tend to open faster than you think!
Replace water regularly.
Extra tips:
The temperature of your refrigerator matters. The colder the better. Although your fridge may not go this low, the best temperature for long-term storage is 32 degrees.
If you plan to take out the stems one by one, wrap them individually. Wrapping them in singles also helps prevent mold spreading form one flower to another. Wrapping them as a small bouquet can work best for shorter-term storage when you plant to take them all out at once.