Yardlong beans (Vigna unguiculata ssp. sesquipedalis) are a subspecies of the cowpea, a legume closely related to the black-eyed pea. This climbing vine produces strikingly long, edible pods and is primarily cultivated in warm, tropical regions of Asia. Although the common name suggests a length of three feet (one yard), this is an exaggeration. Commercially available pods are harvested much shorter than the name implies.
The Typical Length of Yardlong Beans
The pod can theoretically reach up to 36 inches (91 cm) in length under ideal growing conditions, but this maximum size is uncommon in markets. The typical length of a yardlong bean pod, ready for harvest, falls within a range of about 14 to 30 inches (35 to 75 cm). The average length is often closer to one and a half feet, or 18 inches.
The time of harvest is the most important factor influencing the final length and quality. For the best flavor and texture, beans are picked when they are immature and slender, usually between 12 and 18 inches long. If the pods grow much longer, the seeds inside begin to swell, and the pod itself becomes tough, fibrous, and less palatable.
Environmental conditions also determine the ultimate size of the pods. This warm-season crop thrives in high temperatures and can tolerate drought, but prolonged dry spells cause the pods to become shorter and more fibrous. Different cultivars also have varying genetic potentials for length.
Understanding the “Yardlong” Name
The common name “yardlong bean” is more of an aspirational title than an accurate measurement for the edible product. The subspecies name, sesquipedalis, offers a more precise description, as it is Latin for “a foot and a half long,” which aligns closely with the average harvested length.
While the pod can reach the three-foot mark, that length represents the plant’s maximum potential, not the preferred stage for consumption. The name likely arose from the impressive maximum achievable length, which is striking compared to standard beans. This exaggeration is common in horticulture to distinguish a variety. Other common names include Chinese long bean or snake bean.
Distinguishing Yardlong Beans From Standard Green Beans
Yardlong beans are often mistaken for overgrown versions of the common green bean, or snap bean (Phaseolus vulgaris), but they are botanically distinct and possess different physical qualities. The most obvious difference is the length, as the common green bean typically measures only 4 to 6 inches long.
Beyond size, the two legumes differ in diameter and texture. Yardlong beans are noticeably thinner, often described as pencil-width, and they tend to be more flexible and slightly floppy when fresh. In contrast, snap beans are generally thicker, more rigid, and have a characteristic “snap” when broken.
The cooking characteristics also differ significantly. Yardlong beans become waterlogged and bland if boiled or steamed, and are best suited for quick cooking methods like stir-frying.
Another identifying feature of yardlong beans is how they appear on the vine and at the market. The pods grow in pairs, hanging down from the vine, and are frequently sold bundled together in long, serpentine strands. This paired growth pattern and slender form are unique to the cowpea subspecies and distinguish them from the single-pod growth of standard green beans.