Ethyl West emigrated to the Cape Colony with her mother and two brothers. They settled in Port Elizabeth, where her elder stepbrother had a business. On 4 December 1891 she became a member of the Eastern Province Naturalists' Society and at some time also joined the Eastern Province Photographic Society. In 1897 she sent plants to the Cape Government Herbarium. In 1909 she presented 21 plant species from the vicinity of Port Elizabeth to the South African Museum, Cape Town, including a species of Massonia new to the museum's collection. Though she collected mainly in the Eastern Cape, some of her plants are from the Cape Peninsula. Specimens from her are in the herbarium of Albany Museum, Grahamstown; the Bolus Herbarium, University of Cape Town; the National Herbarium, Pretoria; and the National Herbarium, Durban. Her contribution of plants from Port Elizabeth to the Royal Botanical Gardens at Kew, England, was acknowledged in the preface to Volume 4.1 (1909) of the Flora Capensis.
At some time after 1909 Ethyl married Thomas Anderson, manager of the Riet River Syndicate near Douglas. From that time she collected mainly in Griqualand West. Specimens collected under her married name are in the Bolus Herbarium; the McGregor Museum, Kimberley; and the Compton Herbarium of the National Botanical Institute in Cape Town. Altogether she collected over 500 specimens. Her collecting register is in the Albany Museum, Grahamstown. The species Leonotis westiae was named after her.