[horticulturist] Mary Louise Butcher `Polly` Hill (January 30, 1907 – April 25, 2007) was an American horticulturist best known for testing how well plants could survive in cold climates. She founded the Polly Hill Arboretum on Martha`s Vineyard in Massachusetts. Born in Ardmore, Pennsylvania, she graduated in 1928 from Vassar College. Sh...