“The chrysanthemum has its own holiday, Chrysanthemum Day, on the ninth day of the ninth month in the lunar calendar (which is sometimes called Chrysanthemum Month). This holiday is celebrated on September 9 in the solar calendar. The double-nine holiday was once a day of paying tribute to one's superiors

According to one legend, Fei Ch'ang-fang of the Han dynasty advised his follower to take his whole family to the hills on the 9th day of the 9th month. He advised him to make red bags for each member of the family and put a spray of dogwood inside which they would wear while they climbed, and they were to drink chrysanthemum wine at the top of the hill. They followed his instructions and when they returned home in the evening, they found all their domestic animals dead. Since then climbing the hills, wearing dogwood and drinking chrysanthemum wine became traditional activities on this day, as a way to avoid evil spirits and misfortune.

Other activities that are popular include sipping chrysanthemum wine and tea made from chrysanthemum petals, admiring the flowers in gardens and floral exhibitions, and honoring the flowers by painting them and writing poems in their honor.

Hiking up the hill also implies that one will ascend in one’s career. The word nine is homophonous with the word for “long time,” which is one reason that elders are honored on this holiday.

A special chrysanthemum cake called Chung-Yang cake is eaten on this holiday. Because the Chinese words for cake and high sound the same, so one can eat a cake instead of going for a hike.”

http://www.schooloftheseasons.com/flowers/chrysanthemum.html