How to Force Peonies to Open
Sometimes we need blossoms to open before they are ready. Peonies purchased for a special occasion just won't do if they are stubbornly closed. Luckily, if you have no time to wait for nature to take its course, it is relatively easy to force peonies to open. However, not every peony can be forced. Those still growing in the ground must wait for mother nature and hard, immature peonies cannot be coaxed without damaging them. Only soft, pliable blossoms whose petals have begun to separate from the bud can be forced open.
Fill a vase with warm water.
Place each cut peony in the vase one at a time, and cut their stems at a diagonal while holding them underwater.
Place the peonies in warm area: a sunny windowsill, a spot near a warm vent or a pot of steam.
Keep the water warm by changing it frequently until the peonies open in a day or so.
Cut Down Peonies
With their fragrant, multi-petaled flowers, peonies (Paeonia) are a garden treasure that may or may not need to be cut down, depending on which variety you grow. Remove all the foliage, dropped leaves and flowers on the ground to reduce the chances of diseases from lingering to the next season. Cut spent flowers off at any time to give the plant a neat appearance. Tree peonies need no cutting back. But in spring, you can prune away any dead branches or suckers growing from the base of the plant. A hybrid cross between a herbaceous peony and a tree peony, intersectional peonies, such as Takara, (Paeonia 'Smith Opus 2' TAKARA), grown in USDA zones 4 through 8, have the growth habits of herbaceous peonies and the large flowers of tree peonies.
Cut peonies that are forced to open have shorter life spans.