Owen and Vivian Welch Blackwell founded Blackwell Nurseries, Inc. in 1938, and by the late 1960s the nursery became known as the largest azalea producer in the nation, helping earn Semmes the reputation of the "Nursery Capital of the World." Owen Blackwell was an innovator in the industry, and by the mid-1990s Blackwell Nurseries produced three million azaleas for the greenhouse and nursery trade. The Blackwells built the Blackwell House in 1951 on four acres of shaded grounds, and it symbolizes the significance of Semmes as an agricultural and horticultural center. Members of the Blackwell family lived in the home until 2007. Blackwell Nurseries phased out its operation in 2003, and the Mobile County Commission purchased the house in 2011. It currently operates as the Semmes Senior Center and was listed in the Alabama Register of Landmarks and Heritage on July 15, 2021.