Wilhelmina Mary Feemster was born on July 10, 1910, in York, Nebraska, the oldest of four children to parents Howard C. Feemster and Emma L. Groelz. She married physicist Stanley Jashemski in 1946 and moved to the Washington, D.C., area shortly thereafter. Jashemski died on December 24, 2007, at the age of 97.
Jashemski earned her bachelor's degree in mathematics and Latin from York College, Nebraska, where she graduated summa cum laude in 1931. She then served as a public school teacher in Walthill, Nebraska, before beginning the history graduate program at the University of Chicago. She received her doctorate in ancient history from the university in 1942 and specialized in Roman law. Jashemski taught at Lindenwood College in St. Charles, Missouri, from 1942 to 1945. After moving east in 1946, Jashemski began her 34-year tenure in the History Department at the University of Maryland, College Park.
During the course of her career, Jashemski established herself as an expert on the history of the gardens of Pompeii, Italy. She first visited Pompeii in 1955 and became the first non-Italian to conduct archaeological excavations there. Jashemski spent 16 summers in Pompeii and examined more than 600 ancient gardens. Her excavations and research helped develop the field of garden archaeology and led to the publication of her two-volume masterpiece, The Gardens of Pompeii, Herculaneum, and the Villa Destroyed by Vesuvius (volumes published in 1979 and 1993). Later publications include A Pompeian Herbal: Ancient and Modern Medicinal Plants (1999) and The Natural History of Pompeii (2002). At the time of her death, Jashemski was editing a volume on the gardens of the Roman Empire, published after her death.