According to Wikipedia,
“For the Chinese, it (Qingming) is a day to remember and honour one’s ancestors at grave sites. Young and old pray before the ancestors, sweep the tombs and offer food, tea, wine, chopsticks, (joss) paper accessories, and/or libation to the ancestors. The rites are very important to most Chinese and especially farmers. Some people carry willow branches with them on Qingming, or put willow branches on their gates and/or front doors. They think that willow branches help ward off the evil ghosts that wander on Qingming.”
There are many poems about Qingming in Chinese literature. Among them, the most famous one is Du Mu(803-852)’s poem “Qingming”.
qīng míng shí jié yǔ fēn fēn
lù shàng xíng rén yù duàn hún
jiè wèn jiǔ jiā hé chù yǒu
mù tóng yáo zhǐ xìng huā cūn
A drizzling rain falls like tears on the Mourning Day;
The mourner’s heart is breaking on his way.
Where can Winehouse be found to drown his sadness?
A cowherd points to Xing Hua village in the distance.
(the English translation is adapted from wikipedia.)