The Tree Of Happiness

The flowers and bark of the mimosa tree (Albizia julibrissin) are among the most valued of Chinese botanicals for relieving anxiety, stress and depression. Commonly found growing throughout temperate zones in the Western United States albizia is native to China, Persia, Korea and Japan. It is traditionally known as "huan hua" (flowers) and "he huan pi" (bark) and popularly as the "happiness herb," and "collective happiness bark" by the Chinese.

Amazing what you can find out if you try. With thanks to planetherbs.com for the info.

Alternatively try painting a huge smile on any nearby tree (or visit this one). Works wonders.