I believe that this cul-de-sac is incorrectly named, and it is instead an extension of Wild Deer Road. It is named as Wild Deer Road in both Google Maps and Bing Maps, and the street signs are legible in Bing Maps street view that indicate that it is Wild Deer Road. In the Ladue city street map, there is no indication of the "Forest Green Place" name: https://www.cityofladue-mo.gov/mm/files/651_Mapping-Street-Map-2012.pdf