A pencil-thin legume that resembles a green bean except that it can grow up to about 3 feet long (though it's usually picked at 18 inches or less). Yard-long beans belong to the same plant family as the black-eyed pea. In fact, in parts of China the bean is allowed to mature until full-fledged peas are produced in the pod. Yard-longs have a flavor similar to but not as sweet as that of a green bean, with hints of its black-eyed-pea lineage. The texture of the pod is more pliable and not as crisp as that of a green bean. This Chinese long bean, long bean or asparagus bean, can be found year-round (with peak season in the fall) in most Asian markets and some supermarkets with specialty produce sections. Select those that are small (which equates to younger) and very flexible; the peas should not have matured. Refrigerate in a plastic bag for up to 5 days. Yard-long beans are most often cut into 2-inch lengths and sautéed or stir-fried. Overcooking will make them mushy. These beans are rich in vitamin A and contain a fair amount of vitamin C.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.