Stevens was active in various horticultural associations. She was a founding member of the Australian Iris Society in 1948, and the following year she became federal president of the renamed Australian and New Zealand Iris Society. Administrative difficulties led to her recommending a separation of the two bodies, and one result of the split was that she cofounded the New Zealand Iris Society with C. A. Teschner and D’Arcy Blackburn in 1949. She served as its president twice (1949–1951; 1956-1957) and was elected a life member in 1959. Stevens was also the editor of the New Zealand Iris Society for 10 years and registrar of New Zealand cultivars from 1957 until her death. Her writings appeared in New Zealand gardening magazines and in iris publications overseas, and in 1952 her handbook for Southern Hemisphere growers, "The Iris and Its Culture," was published in Australia.