He arrived at Kew in 1893 as a student gardener, gaining experience in several departments until his departure in June 1895 when he was appointed Curator of the Royal Botanic Gardens at Peradeniya in Ceylon (now Sri Lanka). Hugh was to hold that position until 1912, when he became superintendent of all gardens in Ceylon, providing an indication of the significant contribution he made to improving horticultural practices in the region.
In 1910 Hugh published Handbook of Tropical Gardening and Planting with Special Reference to Ceylon. It became a standard text, so successful that it went to a 5th edition by 1962. He also contributed articles to the Journal of Tropical Agriculture and to local newspapers. On retirement from this position in 1926 he moved to Persia (now Iran) and became Horticultural and Agricultural Advisor to the Anglo-Persian Oil Company based at Abadan.
In around 1928, Hugh returned to Britain, settling at first in Ickenham and later moving to Ealing. He had joined The Kew Guild in 1895 and remained a member for almost 40 years. He was a Fellow of the Linnean Society from about 1920 and in 1943 was made an Associate of Honour of the Royal Horticultural Society.
Hugh died in Ealing on 19 November 1948.