Naoru Tanaka , a chamberlain of Japan for Hirohito remembered an episode which took place in September 1965 , on the day Hirohito returned from a 2-month stay from his summer resort . On the previous day , Tanaka had ordered the cleaning of the very thick weed and bush of garden of Hirohito . Hirohito scolded him asking why he ordered the cleaning . He replied that the weed was so thick . Hirohito said that there was no such word as weed . Every plant had its name . Since then , every question of Hirohito concerning plants came to him , although his speciality was geography . Hirohito loved nature , but thought of birds coming to the Palace and he ordered plants for wild birds be planted , such as '' Pyracantha '' , '' Idesia '' , '' Ardisia japonica '' , '' Ilex rotunda '' , '' Ilex serrata '' and '' Viburnum plicatum var . tomentosum '' . According to Tanaka , Hirohito 's idea of leaving old-Tokyo woods in the Palace was based on his experience of the 1923 Great Kantō earthquake ; it should be a place for evacuation
1923 Great Kantō earthquake
1923 Great Kantō earthquake
Biota of Tokyo Imperial Palace