Butterfly pea most likely originated in tropical Asia, although its true origin probably is obscured by its extensive cultivation and naturalization around the globe.
Butterfly Pea, a highly palatable forage legume, generally is preferred by livestock over other legumes. It exhibits excellent regrowth after cutting or grazing but is a short-term plant, producing high yields in the first season and lacking persistence in long term pastures. Butterfly Pea can be grown with tall grasses for rotational grazing, hay, or silage. Butterfly Pea is also used as a cover crop or green manure.
In the Sudan, where it is relatively free from diseases and pests, Butterfly Pea has produced dense cover when grown with a support crop such as Sudan Grass, Sweet Sorghum, and especially Sunnhemp. In Barbados, Butterfly Pea has been established with Elephant Grass (a.k.a. Napier Grass), Guinea Grass, Coastal Bermuda Grass, Rhodes Grass, and Leucaena. Pure stands of Butterfly Pea offer short term high production for “cut and carry” zero-grazing systems; they do not, however, generally yield as much as Lablab Bean or Velvet Bean.
The Butterfly Pea plant is a deep-rooted, tall, slender, climbing legume with five leaflets and a deep blue flower. It is well adapted to a variety of soil types (pH 5.5 – 8.9), including calcareous soils, and precipitation levels, surviving both extended rainfall and prolonged periods of drought. Propagation is by seed; the plants may be grown with support crops or staked with bamboo to facilitate handpicking of the pods.
Butterfly Pea plants generally produce a large amount of seed and will readily self-seed when the dry pods shatter. The seeds are normally sown from the beginning until the middle of the wet season. Butterfly Pea competes fairly well with weeds once established; some weed control can be achieved by mowing the crop, as the successive regrowth of the legume should gradually dominate the weeds. If a pure stand is required, cultivation or hand-weeding will be required during early growth.When cutting the plant to use as forage, cut the plant at least 10 cm (3 in) from the ground. In this way, you should be able to harvest every 42 days. If the crop is being used to pasture animals, you should rest the area for at least 25 days to allow for regrowth.
Harvesting and Seed Production
Total plant protein ranges from 14 – 20%. Seeds contain 38% protein, 5% total sugars, and 10% oil. Nitrogen concentrations of whole tops range from 1.7 – 4.0%.
Pests and Diseases
Butterfly Pea is generally resistant to pests and disease. Various fungi and nematodes have been recorded on Butterfly Pea plants, but damage is rarely bad enough to make control measures economical or practical.
Cooking and Nutrition
Flowers are used to give a blue tinge to rice cakes and boiled rice. The young pods may be consumed like string beans. Leaves are also used to dye food or are eaten as a potherb.