[6] Her father moved the family to Omaha, Nebraska, when she was around 15, and a few years later, in 1860, she married George A. Graves, who went on to work for the war department in Washington, D.C.[4] They had two children, Amy (1861–1892) and Byron (b.

[7] In 1882, they moved to Colorado, where she shifted from figure painting to botanical art, focusing on wild flowers native to America depicted in natural settings.

[9] Her first book was Wild Flowers of Colorado (1885), illustrated with 24 chromolithographs of her watercolors accompanying a description of her travels throughout the state.

Part of the appeal of Thayer's books stemmed from the first-person, diaristic style she used to recount her camping trips and mild adventures in pursuit of unusual flowers in sometimes rugged terrain.

[8] It has been suggested that this alteration was made so that it would not compete so directly with Alice Hill's 1886 book The Procession of Flowers in Colorado.

[8] Thayer also wrote several novels, including An English-American (1889), Petronilla, the Sister (1898), A Legend of Glenwood Springs (1900), and Dorothy Scudder's Science (1901).