In which country does the rose originate?

There is not one country that the rose originated from. In fact the rose predates history by several million years. The rose was widly spread over the northern hemisphere including North America, Europe, the Middle East and East Asia. The word rose is derived from its vibrant color rosa in latin.

oahrs.org/origin.html website no longer exists
rosemagazine.com/pages/yellowrose.asp website no longer exists

The rose is, according to fossil evidence, 35 million years old. In nature, the genus Rosa has some 150 species spread throughout the Northern Hemisphere, from Alaska to Mexico and including northern Africa. Garden cultivation of roses began some 5,000 years ago, probably in China. During the Roman period, roses were grown extensively in the Middle East.

https://web.extension.illinois.edu/roses/history.cfm