Authority on plant hybridization, especially of lilies.
Born in Lancaster, England, Preston emigrated to Canada in 1912. She entered the Ontario Agricultural College (now the University of Guelph) and worked to breed fruit which ripened more quickly and was more resistant to disease and insects. In 1916, she crossed Lilium regale and Lilium sargentiae, becoming the first woman hybridist in Canada. By 1923, Preston had developed this first cross into the acclaimed "George C. Creelman" lily, still often used as a parent for contemporary hybrids.
After 1920, Preston's work continued at the Central Experimental Farm in Ottawa under W.T. Macoun. She made great contributions to ornamental horticulture, producing hundreds of new, hardier species of lily, lilac, crab apple, iris and at least 20 roses, many named after native Canadian Indian tribes. Her lily hybrids alone brought horticultural fame, but she received many other awards, notably from the Massachusetts Horticultural Society and the Canadian Iris Society, both of which also gave her lifetime memberships.
Preston wrote numerous horticultural articles on a wide range of topics. Her book, Garden Lilies, was published in 1929, the first book about lily cultivation written in Canada. She was co-organizer of the North American Lily Society.
The Isabella Preston Trophy was established by the North American Lily Society in recognition of Preston's work. Upon her death, 139 of her gardening and plant books were donated to the Royal Botanical Gardens Library in Hamilton, Ontario.
Sources: Canadian Encyclopedia, 2000 ed.; Molly A. K. Shinhat, Agriculture & Agri-Food Canada, personal communication.