In the 1920s, Crookes founded the Workers Education Association Natural History Club, which became the Auckland Natural History Club. Crookes' early newspaper articles were collected and published as Plant Life in Maoriland: A Botanist’s Note Book in 1926. She published articles on botany in the New Zealand Smallholder and the Auckland Botanical Societynewsletter as well as academic articles in journals including the American Fern Journal. Her research on ferns led her to produce three new editions of New Zealand Ferns, first published in 1921 by H. B. Dobbie. In later life, she lectured on native plants at the Auckland Botanical Society and was a member of the Auckland Philosophical Society. She was also active in conservation, arguing against development that would have harmed areas around the Waitākere Ranges. Specimens that Crookes collected remain in the collections of the Museum of New Zealand (Te Papa Tongarewa).