This paper explains the unique advance of botanical research in colonial Korea by examining the collective scientific practices by both Japanese and Korean researchers within colonial Korea, mostly obscure natural history teachers in colonial schools. Two kinds of politics embedded in their so-called regionalized botanical research explains the success of these researchers with modest backgrounds. In expanding their modest chance to become full-fledged researchers, they overcame the strong ethnic division in the most contested colony of Japan and created common research organizations to promote their cause. They also created a seemingly common cause of regionalized studies of Korean plants while distancing themselves from the universalized study conducted in the Japanese center. Their “cooperative” regionalization was thus a grand political move that aimed to create a regional foundation for their scientific research, a task neglected by the colonial power that promised the “civilizing mission” for the colony. However, the harmony between Japanese and Korean researchers was limited to their common cause of making a research foundation in colonial Korea. Instead of producing a cooperative regionalized study of Korean plants, they produced two regional studies of plants reflecting their contending political positions, a study to Japanize Korea by Japanese researchers and a study to display at least their intellectual independence from Japan by the Koreans. This paper points out that it was the complex intermingling of these two politics surrounding regionalized studies that made botany a successful scientific field, not any intention or policy by the colonial government.