The Town of Flower Mound derived its name from it, it rises 650 feet above sea level, and  it stands 50 feet above the surrounding countryside. Texas' eminent historian, the late A.C.  Greene, believed the hill received its name in the 1840s because of an unusual amount of  wildflowers that grew on it. This area was part of the great American Black Land Prairie  that ran from Canada to the Rio Grande and from the Rockies to the Mississippi. Only  1,000 acres remain of the original 20 million known as the Tall Grass Prairie.