[3] It is widely cultivated for its twining habit and its highly ornamental flowers, 5 cm (2 in) long, which change from white to purple.

In temperate regions it is best grown as a half-hardy annual, sown in heat under glass in early spring, and planted out after all danger of frost is past.

[7] Charles Darwin in 1875 made a detailed study of various climbing and twining plants, subjecting them to stimuli such as light and touch, and presenting them with a range of surfaces while minutely examining their movement over time.

The extremity of each branch is a little flattened, and terminates in a minute double (though sometimes single) hook, formed of a hard, translucent, woody substance, and as sharp as the finest needle.

By lightly rubbing several sub-branches on opposite sides, the whole tendril rapidly assumed an extraordinarily crooked shape.