Born in West Newton, Massachusetts, Hubbard was the older sister of the noted architectural historian Sidney Fiske Kimball. She graduated from the Girls’ Latin School in Boston in 1904 and entered Simmons College later that year. After graduating in 1908, Hubbard worked briefly as an editorial writer for The New England Historical and Genealogical Register. In 1910 she became an assistant in Boston Public Library’s Art Department, becoming the librarian at Harvard University’s School of Landscape Architecture the following year. She remained in the position until 1924, when she married Henry Hubbard. In 1917 she received a Master’s degree in Library Science from Simmons College, with a minor and thesis in English landscape gardening. The following two years she headed the library of the U.S. Bureau of Industrial Housing and Transportation in Washington, D.C. By the 1920s she was teaching at both the Cambridge School of Architecture and Landscape Architecture and in the Landscape Architecture Department at Harvard, where she taught English. After leaving Harvard in 1924 she and her husband co-founded City Planning Quarterly.
Hubbard contributed to such publications as Landscape Architecture (beginning in 1912), House Beautiful, and The Garden Magazine. She also published such books as City Planning: A Comprehensive Analysis of the Subject with James Sturgis Pray (1913); the first landscape architecture textbook, An Introduction to the Study of Landscape Design, with Henry Hubbard (1917); Landscape Architecture: A Comprehensive Classification Scheme with Henry Hubbard (1920); the Manual of Information on City Planning and Zoning with Katherine McNamara (1923); and Our Cities To-Day and To-Morrow with Henry Hubbard (1929). Frederick Law Olmsted, Jr. commissioned her to edit his father’s papers for publication in 1920. Hubbard became an associate member of the American Society of Landscape Architects in 1918. The following year she became the only female member of the American City Planning Institute, also serving as the honorary librarian. Hubbard died at the age of 48 in Milton, Massachusetts.