This tender perennial vine (often grown as an annual) was introduced to Britain from India in 1823 and was often listed as an evergreen climber for hot houses in early 19th-century catalogs. The vine is included in a charming book, The Parlor Garden, which Jefferson's granddaughter Cornelia Jefferson Randolph translated and edited from French in English and published in 1861. The book notes: "The Thunbergia lays hold of any thing that is within its reach, without ever rising very high. It becomes covered with charming flowers, of a fine nankeen yellow, set off with a black spot in the middle. You find it, as well as the passion-flower and the Mandevilles, at all the greenhouses."
American garden writer Joseph Breck described yellow, white, and orange flowered varieties by mid-century and Peter Henderson and William Robinson both recommended it as a half-hardy annual climber for dwarf trellises or against walls. Prefers morning sun and afternoon shade and does not like intense heat. Can be grown in planters and hanging baskets. Grows to 8 feet.
Image curiosity of Forest and Kim Starr (USGS).