ツツジ科ツツジ属の落葉低木で、学名は Rhododendron japonicum。英名は Japanese azalea。
The Japanese azalea (Rhododendron japonicum) belongs to Ericaceae (the Azalea family). It is a small decidous tree that is distributed southward from west-eastern Hokkaido to Honshu, Shikoku and Kyushu in Japan. This tree grows in mostly highlands and can reach 1-2 m in height. The leaves are oblanceolate, alternate and grow fine hairs on the edges. The flowers are vermilion-orange, funnel-shaped, and bloom on the terminal racemes from April to June. The flower has five stamens.