Today's kanji mean "pine, bamboo, include, elegance" and the phrase is said to be from a poem by the Chinese scholar, Liu Yuxi (772-842).
It is an autumn poem, and depicts the still-green pine and bamboo amid the rest of the trees of the forest that are changing color and losing their leaves.
The idea is that the pine and bamboo are admirably constant in maintaining their native color and vigor while the rest of world changes according to whatever is new.
