Phaseolus coccineus (Runner Bean)

Runner beans differ from common beans in that their cotyledons remain underground during germination (hypogeal germination) rather than being pushed above the soil, and they possess tuberous roots that allow them to be perennial in mild climates. They also prefer cooler growing conditions than common beans and produce much larger, more conspicuous flowers, typically scarlet red.

Yes, runner beans are fully edible at multiple stages—young tender pods are eaten as a vegetable similar to green beans, while the large, starchy mature seeds can be harvested and cooked as dried beans. The flowers are also edible and are sometimes used as a colorful garnish in salads.

In their native highland regions of Central America, Phaseolus coccineus is naturally perennial, surviving year to year through swollen tuberous roots. In temperate climates where frost kills the above-ground growth, gardeners in mild-winter areas can sometimes overwinter the roots by mulching heavily, though most growers treat them as annuals.

Runner beans became a staple of British kitchen gardens after being introduced to Europe in the 17th century, and the cool, moist UK climate suits their growing preferences. In the United States, the common green bean (Phaseolus vulgaris) has traditionally dominated, and many American palates find the runner bean's somewhat thicker texture and distinctive flavor unfamiliar.