This sentence comes from the second paragraph of Li Weng's fourteen cold to the clouds, which is a collection of works created by Li Yu, a writer in the late Ming and early Qing Dynasties.
Zhao Hu, also known as Zhao Bo, is said to have a Gan Tang tree in his residence. After he left, people took extra care to protect the tree, and wrote a poem named "Gan Tang" as a souvenir.