May & October
The rose for ornament is written in Kokin Wakashu, or Collection of Ancient and Modern Japanese Poetry, the first anthology of Japanese poetry compiled by Imperial command in early 10th century while the rose with a focus on its thorn is shown in Manyoshu, or Collection of Ten Thousand Leaves, the oldest extant collection of poems in Japan, compiled from the late 7th century to the late 8th century.
Japan is known as one of the natural habitats for roses. Modern roses are derived from some roses native to Japan and those of some other countries in Asia, including China. After World War II, roses became popular among common people like these days in Japan. Roses are hardly found in the traditional gardens of Japanese castles, temples and shrines.
Handayama Botanical Garden & Hikasa Rose Garden