Mary Gibson Henry (1884-1967) was born August 15, 1884 in Jenkintown, Pennsylvania to Susan Worrell Pepper and John Howard Gibson. Her great grandfather, George Pepper, had been a member of the first Council of the Pennsylvania Horticultural Society and had the first greenhouse in Philadelphia. Her grandfather also owned a greenhouse and was deeply interested in horticulture. Her father was an avid outdoorsman. Mary’s formal education ended when she graduated from the Agnes Irwin School in Philadelphia in 1902. However, her study of nature intensified as she traveled with her family to the Grand Canyon and the Colorado Rockies and climbed Mont Blanc on a trip to Europe in 1908.

In 1909, she married Dr. John Norman Henry ( -1938). The couple had five children. As her children were growing up, Mary developed a large kitchen garden and experimented with native rock plants on the family’s property in Maryland. Meanwhile, she cultivated orchids in a small greenhouse at the family’s home in Philadelphia. She also read extensively about botany and horticulture. In 1926, the Henry family purchased a 95-acre farm in Gladwyne, Pennsylvania near Philadelphia. After nearly two decades of marriage, she began her active expeditionary career as a field botanist the following year. She went on over 200 botanical expeditions over the next forty years and collected floral specimens that she donated to the Royal Botanic Gardens of Edinburgh and the Academy of Natural Sciences in Philadelphia. Early on, she explored the Atlantic Coastal Plain, the Piedmont Plateau and the Appalachian Mountains. Then, in the 1930s, she made four exploratory trips into largely uncharted territory of British Columbia with a Canadian government topographer, K. F. McCusker. Her husband and four children accompanied her on the first expedition and her daughter, Josephine, joined her on the three subsequent journeys. In 1931, the Department of Lands of British Columbia named a mountain in her honor, Mount Mary Henry. Her 1935 expedition in British Columbia formed the basis for the planning of the Alcan Highway.

In her garden at Gladwyne, Mary developed hundreds of hybrids from the seeds and cuttings she brought back from her trips. Although she continued her botanic expeditions until her death, she focused on expanding her garden after her husband’s death in 1938 and soon offered her plants to nurseries for distribution. During her career, she also wrote over one hundred published articles on horticulture and botany and gave numerous lectures in the United States and abroad. She served as president of the Philadelphia Botanical Club, council member of the Pennsylvania Horticultural Society and director of the American Horticultural Society. In 1941 she became a research associate in the department of botany at the Academy of Natural Sciences, Philadelphia. In the same year, the Pennsylvania Horticultural Society awarded her the Schaeffer Gold Medal for her “notable contribution to horticulture.” She was also named an honorary fellow of the Botanical Society of Edinburgh. In 1950, she created and permanently endowed the Henry Foundation for Botanical Research at her Gladwyne estate. The Foundation is dedicated to the collection and preservation of choice American native plants. In April 1967, Mary died on a collecting trip to North Carolina at the age of 82.