The garden nasturtium (Tropaeolum majus Linnaeus) is not a Nasturtium or water-cress. The apparent misnomer dates back to the late 1500s. In his Herbal (1633 ed.) written in 1597, John Gerard states he had received seeds from a friend in Paris. He believed the seeds had come from India by way of Spain to France. Gerard called them, Nasturtium Indicum, "...for the smell and taste shew it to be a kind of Cresses."

The cresses are members of the Brassicaceae [brass e ka' se ee], the crucifer or mustard family. Crucifers are known for the presence of isothiocyanates and the strong, peppery flavor the chemical imparts to the plants. But garden nasturtiums, in the Tropaeolaceae [tro pe o la' se ee], share no characteristics with the crucifers except the isothiocyanates.

The original Tropaeolum majus is a scrambler, the vine growing three to ten feet in length and useful in flower beds where spring bulbs had finished flowering or to hide stumps or brush. The nasturtium climbs by means of tactile petioles, the 'leaf-stems' bending toward any object they happen to touch. Most modern cultivars are dwarf forms, bred to fit window boxes and small flower beds.

Linnaeus named the genus from the Latin tropaeum, a mark, token, or shield; a reference to the leaves shaped like the circular shields carried in battle.