 To colonists, "herb" meant not only savory plants added to dishes to enhance flavor but included medicinal plants as well as greens (such as nasturtiums and calendulas) meant to be eaten raw or cooked as part of a salad.The Colonial Revival gardening movement traces its origins to the Centennial International Exhibition of 1876, the first official World's Fair held in the United States.The Centennial Exposition was held in Philadelphia, Pennsylvania, from May 10 to November 10, 1876, and it celebrated the 100th anniversary of the signing of the Declaration of Independence.