From which ancient poem do "April Qing" and "Rain at First Clear" come?

It's from Sima Guang's "Early Summer among Guests" in the Song Dynasty

Original text:

April is clear and the rain is clear, and Nanshan is clear.

there is no catkin because of the wind, only sunflower leans towards the sun.

Translation:

In early summer and April, the weather was clear and warm, and it just cleared up after a rainy day. After the rain, the mountains were greener and more pleasant, and Nanshan, opposite, became clearer. There are no catkins fluttering in the wind, only sunflowers are blooming towards the sun.

Note:

(1) Among the guests: living in a foreign country as a guest.

(2) Harmony: The weather is clear and warm.

(3) Nanshan is the household: Nanshan is opposite the door.

(4) only: only, only.

Living in his hometown, at the end of spring and the beginning of summer, a beautiful picture of sunny, clear and warm after the rain jumps into the poet's field of vision. In this changing picture, the poet doesn't like the rainy Nanshan, nor does he praise the catkins dancing in the wind, but gives his unique bell to the sunflower leaning towards the sun. What is the meaning? It's not difficult to find that the poet doesn't love sunflower alone, but because of his temperament. However, in any case, I don't want to "bow my eyebrows" and sway with the wind. I finally chose to be a sunflower that grows to the sun. It is really golden, smiling and knowing how to cherish the sunshine. Perhaps this is the loveliness of sunflower!