This is the 2308th most frequent Chinese word.
青
"青" means green, blue, or youthful.
青 means 'green' or 'verdant' in this context, describing the lush, green vegetation that persists through the changing seasons.
我的家乡四季常青。
My hometown is evergreen all year round.
青 is used as a color, typically indicative of green or blue shades depending on context, here referring to the green color of the shirts.
他年轻时喜欢青色的衬衫。
He liked green shirts when he was young.
青 is combined with 松 (pine tree) to specify the green color of the foliage, and is used metaphorically to symbolize qualities associated with pine trees.