1. It means that spring is getting longer and longer, so it is late.
2. The whole meaning of the beautiful scenery in the late days is: how beautiful the scenery is when the mountains are bathed in spring. The spring breeze brings the fragrance of flowers and plants. It comes from "Two quatrains (one of them)" by Du Fu of the Tang Dynasty.
3. Original
In the late days, the mountains are beautiful, and the spring breeze is fragrant with flowers and plants.
Swallows fly when the mud melts, mandarin ducks sleep when the sand is warm.
4. Translation
Rivers and mountains are bathed in spring. How beautiful it is. The spring breeze brings the fragrance of flowers and plants. Swallows are busy building their nests with wet mud in their hands. Mandarin ducks sleep in pairs on the warm sand.