[1] In 1873, Jenman moved to Jamaica where he was appointed as superintendent of Castleton Botanical Gardens.
During this time he began his work on ferns of the Caribbean, which was his major contribution to the field of botany.
[1][2] In 1879 Jenman moved to British Guiana where he was appointed as Government Botanist and Superintendent of the Botanical Gardens.
Castellani House, now the home of Guyana's National Art Gallery, was originally designed and built to be his official residence by the Maltese colonial architect Cesar Castellani.
[6] In 1897, botanist Wilhelm Wächter published Jenmania, which is a genus of fungi within the family Lichinaceae and named in George's honour.