Green began his botanical career in 1954 as assistant botanist in the Western Australian Herbarium. He remained in that position until 1958, in his final year serving as botanical adviser to phytochemical surveys in the southwest.
Green commenced his botanical work in 1954 as an assistant botanist at the Western Australian Herbarium. He continued in this role until 1958, with his final year involving advisory duties for phytochemical surveys in the southwest.