Born in Brooklyn, New York, Blossom graduated from the Pratt Institute High School and Amherst College. After graduation, he worked on a fruit farm before continuing his studies at Harvard’s Lawrence Scientific School, becoming the first student to graduate with an M.L.A. in 1907. While at Harvard, he began working for Olmsted Brothers and befriended Frederick Law Olmsted, Jr., and Percival Gallagher. In 1908 he married Minnie Motley Dawson, sister of his colleague James Dawson. At Olmsted Brothers, Blossom worked under various principals to draft plans and devise planting plans for projects including South Mountain Reservation in New Jersey. He traveled often on behalf of the firm: with Dawson he attended the Alaska-Yukon-Pacific Exhibition in Seattle and visited Cuba for the planning of a resort community. In 1911, he represented Olmsted Brothers in planning the 1915 Panama-Pacific Exposition in San Diego. When Olmsted Brothers resigned from that project, Blossom returned to the northeast, working mainly on residential estates, particularly in Newport and on Long Island. In 1919, he left the firm to start his own practice focusing primarily on the New England area, retaining many of his residential clients. Rheumatic fever in his youth caused Blossom to suffer heart problems all his life. He died in 1935 of cardiac failure at age 56.