In ancient China, when friends or relatives were separating, they would pick a willow twig (柳条) and give it to the person who was leaving. This was to express (they)wish for him to stay. In Chinese, the word for "willow" is pronounced the same the word for "stay."
Many Chinese poets liked writing about willows in their works. One of (famous) poems is A Farewell Song (《送元二使安西》) by Wang Wei. It reads, No dust is raised on the road wet with morning rain, The willows by the hotel look so fresh and green.
I invite you (drink) a cup of wine again, West of the Sunny Pass no more (friend) will be seen.
Nowadays, willow twigs can also be seen in modern art. There was an amazing performance about willow twigs. 365 people (hold) willow twigs in their hands on the green stage. At the same time, ancient painting of weeping willows (垂柳) appeared on the LED screen. The setting of 365 people stood for 365 days, and the colour green meant the return of spring. The performance (praise) highly by the audience. "I was (deep) attracted by traditional Chinese culture," one of them said.
In short, giving a willow twig to a person is not saying goodbye asking him to stay. This is the beauty of Chinese culture.