In the tropics, it is a perennial plant, and depending on the variety, will grow 3 feet (1 metre) to 20 feet (6 metres) tall.
Lablab Beans have attractive foliage and flowers that may be purple or white depending on the variety. The purple variety is often referred to as “Red.”
In the Western World, Lablab is grown as an ornamental, as Scarlet Runner Beans once were. You will see names such as Purple Hyacinth Bean Vines, Coral Vine, etc for the purple variety.
Some varieties are better for their dried beans; some are better for their pods to be used as fresh beans.
- Papri (aka potetti): Grown for its beans, which are brown with a white stripe when mature and dried;
- Siem: Grown for its flat, fleshy pods used as fresh beans;
- Val: grown for its beans to be dried.
The pods can be green or purple, though the purple turn greyish when cooked. To be eaten as fresh “green” beans, the pods must be harvested young as they go fibrous very quickly. They are not a stringless “green” bean. The purple-podded ones are used more as a fresh bean than the green-podded ones, because the green pods often get tough too quickly.
The colour of the dried beans can be cream, brown or reddish-brown. They will have a white mark along one side. They must be soaked and peeled before use.
In Indian stores, they are sold both already peeled and split under the name of “val dal.”
In Asia and Africa, young Lablab leaves are used as a potherb, and steamed and eaten.
The plant can also be grown as animal forage or silage. In this case, the beans are often eaten by people, with the rest of the plant harvested for the animals.
For use as a fresh “green”, the plant needs 60 to 70 days from seed; when being harvested for dried beans, 150 to 200 days from seed.
Nutrition
Mature Lablab Beans have two toxins in them, trypsin inhibitor and cyanogenic glucoside. They need to be cooked before eating to destroy these toxins. Reputedly, some say it is safe to eat very young beans raw, but it is uncertain how young they have to be to be safe to eaten like this.
Some toxins may leach into the cooking water that some people may be allergic to, so throw the cooking water away. [1]
[1] Hodgson, Larry. Annuals for Every Purpose. Rodale. 2002. pp 234-5.
History Notes
Lablab Beans have been grown in parts of Africa since at least the 700s.
Sources
Aganga, A. A. and S. O. Tshwenyane. Lucerne, Lablab and Leucaena leucocephala Forages: Production and Utilization for Livestock Production. Pakistan Journal of Nutrition 2 (2): 46-53, 2003.