Peony is a king of flowers. If rose is a queen, then the king is surely peony.
Luxuriance and incredible aroma of peonies captured hearts of many people.
Peony symbolizes wealth, nobility, and wellbeing. In addition, peonies are considered to be helpers in love and personal life. 
In ancient Greece peony was a symbol of longevity. 
Flowers are language of nature. It is real and sincere. Learning symbols of flowers we can choose a state and mood that we would like to stress or intensify due to jewelry with real flowers. 
Floriography is symbols attributed to different flowers and used to express moods and feelings.
In the Victorian era the language of flowers was used to express feelings which could not be spoken aloud. The language of flowers finds its roots in the East. Knowledge about the language of flowers was brought to Europe by two women: Aubry de la Mottraye and Lady Mary Wortley Montagu.
Name of the flower is formed from Greek word paionios that means healing, curative.
Cultivation of peonies was started in China over 2,000 years ago. According to Chinese sources, interest to peonies as ornamental plants began during a period of Qin and Han dynasties.  
Legends about peonies wee made up not only in China but also in Europe though they were not connected with ornamental but healing properties of the plant. In the late XVIII century peony was brought from the East to Paris where gardeners paid big money for it. In the early XX century elegant peonies became best sellers at a flower market. But along with appearance of new exotic flowers interest to peonies was waning, they were considered to be old-fashioned, and starting from the 30ies for over 60 years they could be found only in the most distant corners of gardens.
Peonies are glorified in poems. Peonies are painted on canvases.
There are a lot of legends about the king of flowers but the most popular is a Chinese legend: 
Ho Chi, devotee of peonies, had only peonies in his garden. The flowers were of all colours and incredibly beautiful. When in the beginning of summer peonies began to bossom, the garden became wonderful and it was named a “garden of one hundred flowers”.
Once Chang-Ay, a mandarin’s son, went by the garden. Having seen the beautiful garden he came rushing and started to destroy it. 
Having got angry the old man beat up the mandarin’s son and pushed him out of the garden. Ho Chi was sitting in the devastated garden and crying bitterly for a long time. Suddenly he saw a good-looking girl who addressed him with the words, “Bring me water and I will revive your flowers”. When Ho Chi came with water, the girl disappeared but the garden became even more wonderful, and the peonies were even more luxuriant and had unusual colours. Flowers of different species can be seen on one bush.
Thereafter Chang-Ay blamed old Ho Chi in witchcraft and he was sentenced to death. Chang-Ay went to the ‘garden of hundred flowers’ and started to destroy wonderful plants again. Suddenly a strong wind arose and all peonies turned into young girls wearing dresses resembling flower petals. They began to wave by loose sleeves and the strongest hurricane broke out.
Caught be the wind Chang-Ay was raised so high that having fallen to the ground he plunged to death. Having learnt about that a judge reversed the sentence and dismissed Ho Chi.
Looking after his flowers the old man became younger and lived for a long time. It is said that those who love flowers and protect them bring joy to people and themselves.
Ancient Greek legend is also excellent. 
Goddess of flowers Flora looked for a helper. The main candidate was a rose. Being amazed by its magnificence all flowers present in a meeting unanimously agreed that Flora’s helper would be the rose. And only a peony was against. He thought itself more beautiful and better than the rose. The peony was so loud in its protests that Flora could not stand it that told, “Proud, stupid flower!”, she said, “Stay always so fat and bloating as not you are because of your complacence”. The peony reddened with shame. It is the story how the saying “Reddened as a peony” appeared.
Peony is still an adequate competitor of rose. Dedicated followers of roses are coquettish by their nature but admirers of peonies are grand. 
Peony is beautiful, proud, and elegant.