What poem does "green flowers are leisurely in my heart" come from?

From The Book of Songs Zheng Feng, this poem is about a man waiting for his lover on the rostrum.

Original text:

The Book of Songs Zheng Feng Ji Zi

Qingqing is your collar, YY is my miss. If I didn't go to see you, didn't you receive my letter?

Green is what you wear, and leisurely is my feeling. If I never visit you, can't you take the initiative?

Come on, always open your eyes, on this high tower. A day without seeing your face seems as long as March!

Translation:

Green is your collar, and leisure is my mood. Even though I didn't go to see you, didn't you receive my letter?

Green is what you wear, and leisure is what I miss. Even if I didn't pick you up, couldn't you come voluntarily?

Come and go, look around, on this tower. I haven't seen you for a day, like three months!