Greenery Day is a national holiday in Japan, celebrated annually on May 4th. The holiday is part of Japan's 'Golden Week', a cluster of holidays in late April and early May. Greenery Day is a day that fosters a sense of appreciation and harmony with nature. The holiday resonates significantly with the Japanese culture which has a deep-rooted and profound connection to nature.

The holiday was originally celebrated on April 29 and was closely tied to the birthday of the late Emperor Showa (Hirohito). Emperor Showa had a love for plants and nature, and after his death in 1989, Greenery Day was established to honor his memory. However, in 2007 Japan reassigned Emperor Showa's birthday to be Showa Day, and Greenery Day was moved to May 4th.

On Greenery Day, Japanese people are encouraged to reconnect with nature and show their gratitude for its blessings. Many use this day to plant trees, do some gardening or go out for a walk in the beautiful and lush parks around the country. It is a day that provides an opportunity for people to get close to nature, and to think about their role in environmental conservation and protection.