Yardlong beans

Despite its name, the yardlong bean rarely reaches a full yard. Its slender pods are more commonly harvested at about 30 to 60 centimeters, while they are still crisp and tender. It is also not a true bean of the common-bean species: botanically, it is a specialized form of cowpea.

That distinction explains its layered origin. Cowpeas were domesticated in Africa from wild relatives of Vigna unguiculata. As cultivated cowpeas spread eastward, farmers in South or Southeast Asia selected plants for unusually long, succulent pods that could be eaten fresh rather than left to mature for dry seed. The resulting vegetable became the yardlong bean, also known as asparagus bean, snake bean, or Chinese long bean.

Its precise early development is difficult to assign to one modern country, but the crop became deeply established across tropical and subtropical Asia. It is prominent in Chinese, Filipino, Thai, Vietnamese, Malaysian, Indonesian, Indian, and Sri Lankan cooking, where the pods are stir-fried, curried, braised, pickled, or served raw in some regional dishes.

Today, yardlong beans are grown throughout warm parts of Asia and Africa and as a specialty crop elsewhere. In the United States, commercial and market-garden production is concentrated in warm regions and areas serving Asian communities, including California, Florida, and Hawaii. The plant thrives in heat and can produce rapidly, but its pods are best picked young, before the seeds swell and the walls become fibrous.