Early Butternut squashes were believed to have originated in the United States in the 1930’s as a natural outcrossing or mutation of the Canadian crookneck squash. In 1940’s an amateur. breeder Charles Leggett with the help of the Waltham family at the Waltham Agricultural Experiment field station helped to popularize his Butternut squash. 1970 All-America selections winner. Waltham has a creamy, rich, dry yellow-orange flesh with a nutty flavor.