Albizia julibrissin is a deciduous broad-leaved tree native to Japan, Korean Peninsula, and China, etc. The Japanese name, Nemunoki, which means "Tree of Sleep," comes from the fact that its leaves slowly close together and hang down at night, associates with the image of felling asleep.In China, it is also an auspicious tree that is considered a symbol of marital bliss. That is where the Kanji of "合歓木" derives from, which means "combine and feel happy."