Today, the mansion's parlor ceiling is covered in oak taken from the folding doors and staircase of the Main Street home. Louis Linnenberg, who managed the Scanlan estate, is said to have built the brick wall in front of the mansion from the stacks of the original plantation sugar mill. Lillian and Stella Scanlan lived in the rebuilt mansion on the plantation until their deaths in 1948 and 1950.

Sienna was run as a working ranch by the Scanlan sisters. Much of the land cultivated for growing sugar cane and row crops was allowed to return to pasture and woodlands, but the plantation cannery, which stands today next to the sugar barn, remained in use until 1950. Having no direct heirs, the Scanlan sisters created the Scanlan Foundation, a charitable trust administered by Linnenberg and benefiting various Catholic charities. From 1955 to 1967, the Catholic Diocese of Houston-Galveston used the plantation as the Cenacle Retreat. The bell that once called plantation workers to dinner was used to call the Cenacle Sisters to prayer.

Massive live oaks, some more than two centuries old, exist as a reminder of the epic time when Stephen F. Austin, the "Father of Texas," walked beneath their branches and early colonists explored the bends in the Brazos River and established the crossing at Oyster Creek. Also recalling the past is the Scanlan Mansion, carefully restored during the first stages of Sienna Plantation's development as a master-planned community. Revering its ties to the past, Sienna is once again making history. New settlers are weaving plans for the future with a profound respect for the visionaries who nurtured the promise of Sienna Plantation.