Miss Ellen C. Steedman was appointed principal of the English-medium Eunice High School for girls in Bloemfontein on 5 October 1901 and became a member of the Philosophical Society of the Orange River Colony in 1903. She served on the society's committee from 1904 to 1908, and as joint vice-president for 1908/9. On 9 April 1904 she read a paper before the society on "Adaptation of plants to their environment", of which an abstract was published in its Transactions (1903-1907, Vol. 1, p. 28). She compared the flora of South Africa to that of other countries and showed how it had adapted to local conditions of the soil and climate. The paper was amply illustrated by lantern slides and specimens of plants.
By 1910 Miss Steedman had obtained the degree Master of Arts (MA) and was a member of the South African Association for the Advancement of Science. At that time she resided at Gando Farm, and later at Norfolk Farm, both near Gwelo (now Gweru, Zimbabwe), where she farmed for the rest of her life. She became a member of the Rhodesia Scientific Association in 1923 and from 1925 published several contributions on the trees and shrubs of the territory in the association's Proceedings. These contributions, comprising some 200 descriptions of species and 84 plates, formed the basis of her book, A description of some trees, shrubs and lianes of Southern Rhodesia (Bulawayo, 1933, 191p).