Bellflower is a city in Montgomery County, Missouri, United States. The population was 325 at the 2020 census, down from 393 in 2010. A po…Bellflower is a city in Montgomery County, Missouri, United States. The population was 325 at the 2020 census, down from 393 in 2010. A post office called Bellflower has been in operation since 1887. The community was named for bellflowers near the original town site.