Marian Spore Bush was born Flora May Spore in Bay City, Michigan, on October 22, 1878, to Melvin and Helen Miller Spore.
According to her sister Belle Spore Tunison, "although a woman of varied interests, Mrs. Bush never had the slightest inclination towards art--either theoretically or in practice--until after the death of her mother, Mrs. M. L. Spore, in 1919.