The Scottish botanist Philip Miller (1691-1771) established the genus Watsonia in 1758 to honour the English naturalist and physician, Sir William Watson (1715-1787). Watsonia humilis was first described by Philip Miller in the 8th edition of The Gardener's Dictionary , published in London in 1768. The specific name humilis is descriptive of the short stature of the plant, but it is by no means the shortest member of the genus, as that distinction belongs to W. minima, an orange-red-flowered species from the Riviersonderend Mountains, whose flowering plants are sometimes as short as 100mm. A synonym of the white form of Watsonia humilis is Watsonia roseo-alba.

Historically, the specific name humilis has often been misapplied to pink and purple forms of Watsonia coccinea, which are superficially similar. This has led to a lot of confusion, which continues at present. Watsonia coccinea also occurs in the southwestern Cape, from Malmesbury to the Cape Peninsula and east to Bredasdorp, but differs mainly in having a longer, strongly curved perianth tube, obovate (inversely oval) tepals and the upper tepal usually forms a hood over the anthers. In addition, it favours different habitat on moist sandstone flats. The common name `waspypie', which is sometimes applied to W. humilis, actually refers to W. coccinea .

The genus Watsonia has 52 species and is endemic to South Africa, Lesotho and Swaziland. It comprises winter-growing, summer-growing and evergreen members and its main centre of diversity is in the southwestern part of the Western Cape. One of the best-known species in this area is the pink or mauve W. borbonica subsp. borbonica which is seen flowering in large colonies after fires. The pure white W. borbonica subsp. ardernei is a favourite garden subject and the mauve- or rarely white-flowered W. marginata has greenish-grey leaves and prominent thickened margins. Th e gigantic red-flowered W. vanderspuyiae has the largest corms, broadest leaves and tallest flower stems of all the species and W. hysterantha is exceptional in that its leaves are hysteranthous, appearing after the flowers.