William Watson, British horticulturalist, worked at the Royal Botanical Gardens at Kew, near London, from 1879 to 1922. He was appointed curator of the gardens in 1901. In 1886 he described "Cape bulbs" in the Gardener's Chronicle. The next year he visited the Eastern Cape, mainly for health reasons. After landing at Port Elizabeth towards the end of February he travelled to Grahamstown (where he spent two weeks), Port Alfred, King William's Town, East London and Cape Town, and met the local horticulturalists and plant collectors William Armstrong, E.E. Galpin* and James Leighton*. He made observations of the indigenous and cultivated plants of the region and the factors affecting their cultivation such as climate and rainfall, giving particular attention to the contrast between the winter and summer rainfall regions. The seeds, bulbs, live plants and herbarium specimens he collected went to Kew Gardens. He described his visit in "A month at the Cape" in the Gardeners' Chronicle (1887).
Watson published many articles in the Gardener's Chronicle and other British horticultural journals from 1884, among them notes on bulb plants, cycads, proteas, etc. that he had encountered in South Africa. For example, "Nerine bowdeni" (Family Amaryllidaceae; Gardeners' Chronicle, 1904; Botanical Magazine, 1907), "Aloe nitens" (Botanical Magazine, 1907), "Arctotis decurrens" (Family Compositae; Ibid, 1907), and "Raphionacme utilis" (Family Asclepiadaceae; Ibid, 1908). He was also the author of severalbooks: Cactus culture for amateurs (London, 1889, with later editions to 1920), Orchids: their culture and management (New York, 1890), Rhododendrons and azaleas (London, 1910), and Climbing plants (London, 1915). The species Hebenstreitia watsonii was named in his honour, while Volume 130 (1904) of Curtis's Botanical Magazine was dedicated to him.