What does it mean that green willows are everywhere in spring?

This is a poem describing the revival of everything in spring.

This means that in spring, the willows turn green and all the branches sprout. Red and delicate peach blossoms are blooming all over the mountains.

Willow covered with long green branches, swaying in the wind, as if gently stroking the bank. The evaporated water vapor between Shui Ze and vegetation condenses into smoke. Willow seems to be intoxicated with this beautiful scenery.