Horticulturally known as Dolchios lablab and Lablab purpurea, Dolichos lablabeds, Bonavist, (Family: Fabaceae), it is grown in China as an edible. In America, gourmets are slow to adapt to serving them on salads. The lovely lavender flowers are edible, too.
In China they are called pig-ears.
I just received my copy of "Food Plants of the World: An Illustrated Guide" by Ben-Erik van Wyk . Hyacinth Bean is described as a perennial vine but that only applies to zone 10 and 11 and above.
Van Wyk says the pods are used to make a soy sauce like condiment in Myanmar. The plants are widely grown in Africa, India and Southeast Asia. The dry beans are 25% protein and are mineral rich.
The University of Kentucky agriculture department suggested that they would be perfect as "a natural product for cut stems for the cut flower industry. In addition, the pods are so unique that they could be used to decorate salad bars or harvested for ethnic food wholesalers."
The plants are not sold in stores but the seeds are readily available.
Many gardeners complain about a low germination rate with Hyacinth Bean Vine seeds, probably because we all are over-eager to get them growing and start them before the heat they need is available.
Like all pea family plants, legumes, they attract few insects, have no diseases to speak of, and draw nitrogen out of the air to deposit in the soil.
A Lake Country Point of View blog author provided an in-depth exploration of the plant's history and culture.
Misouri Botanical Garden in St. Louis includes this beauty in its Plants of Merit list.
This is a plant you will be glad you have in August, September and October. Plan to plant some seeds next June.