William H. Wormald resided in East London by 1871, and practiced there as a solicitor. In 1888 he was appointed Town Clerk, serving until August 1896, when the town council demoted him to curator of the Queen's Park Botanical Garden. His demotion caused a public outcry, but efforts to rescind the decision were unsuccessful. He assumed duty as curator of the garden on 1 February 1897, succeeding Charles Franz, and held the position until 1903. At first he went to great effort to beautify the garden and encouraged the donation of plants from various sources. However, after 1898 East London entered a period of extreme drought, which lasted to about 1904. During this period the town's water supply dried up completely and the garden was severely strained.
In 1890 Wormald was a country member of the Eastern Province Naturalists' Society, founded in Port Elizabeth in 1884. The short-lived East London Natural History Society appears to have been formed in 1891, and Wormald was its honorary secretary for the next three years. In 1896 he presented plants to the Cape Government Herbarium. Many years later, in 1919, he became a member of the South African Association for the Advancement of Science. At that time he was a Fellow of the Royal Horticultural Society. He was still living in East London in 1921. The plant species Iso?tes wormaldii was named after him by T.R. Sim*. He was probably the father of Miss K. Wormald*, who also collected plants.