Little Known Legumes

Velvet bean – Mucuna species
This fast growing annual legume thrives in moist tropical conditions. In South and East Asia velvet beans were originally cultivated as a green vegetable. There are around 5-12 cultivated Mucuna species, some distinctions between types are confused. Types are very variable, seed colours can be shiny black, creamy white, gray, beige and mottled, average time to pod maturation ranges from 100 to 300 days, and not all are edible.

Velvet bean is an excellent green manure, useful in crop rotations and for inter-cropping. As a legume the plant roots enrich the soil with nitrogen, it makes much growth quickly and covers the ground and smothers weeds. Use of the “fertilser bean” has spread spontaneously by innovative small farmers in Africa and Latin America over the last 20 years. Edible velvet bean varieties contain around 27% protein and are a good source of minerals iron, potassium, calcium and magnesium, and amino acids. They are boiled, roasted or fermented.

Disadvantages: Before consumption the seeds must be treated by being cracked open and removed from the seed coats and then soaked to remove a toxic principle

PERENNIALS

Apios or Groundnut – Apios americana
A vigourous perennial, unusual amongst legumes in that both the tubers that form along the roots, and the seeds are eaten. . To the native people living in what is now the eastern United States apios was a staple food gathered from the wild. The tubers are very well flavoured, sweet and nutty and contain up to 16.5 % protein, 3 times that found in potatoes. Despite very good attributes as a food crop the plant is yet to be widely cultivated and domesticated forms of groundnut have not been developed. It is at home in wet soil, in it’s native habitat it flourishes along the banks of rivers and streams where it spreads itself by tubers washing downstream as banks are eroded.

Very easy to grow as an annual or as a perennial. The vine is killed by frost but the tubers survive winters even into southern Canada and are believed to be hardy to at least –20 degrees Celcius. Tubers can be harvested from the first year of growth, although it takes 2 – 3 years to get sizeable crops. They may be left in the ground and dug as needed or may be dug up in the autumn and are stored.

NB: The groundnut shares the rhizobial strain of the soybean, depending on the site, inoculation may be advisable for optimum performance.

Winged bean, aka Asparagus pea and Goa bean,
Psophocarpus tetragonolobus
Believed to originate in the islands from Papua New Guinea and modern day Indonesia, the winged bean is grown today in rural areas throughout Southeast Asia. It is a high climbing perennial vine, utilised as edible pods, green seeds and dried seeds as well as leaves, flowers and in some varieties the edible tuberous roots. Dried seeds can be steamed, boiled, fried, roasted, fermented, or made into milk or fermented to make a tofu. Tubers can be boiled, steamed, or baked.

The seeds are comparable to soybean in composition and nutritional value and contain similar proportions of protein (30-40%), carbohydrates, oil, minerals, vitamins and essential amino acids
The tubers are rich in carbohydrates (25-30%) and proteins (10-15%). The plant is believed to be one of the best nitrogen fixers. It is a tropical plant that is generally requires a short day length to flower and produce seed. There are varieties that do not share this trait and can be grown as annuals in temperate regions.

Ahipa – Pachyrhizus ahipa
Ahipa is closely related to jicama, Pachyrhizus tuberosa, known as the potato bean, both plants originate and were first cultivated in South America. Jicama or Yacon is a perennial climber up to 6 metres tall cultivated also in tropical Asia for its edible roots. Ahipa is little known outside remote parts of the Andes and landraces are disappearing there, although it probably has potential as a food crop in a wider variety of locations than jicama. Ahipa is a smaller and non-climbing plant that matures faster and is not day length sensitive like its cousin.

Tubers of both ahipa and jicama are generally eaten raw in salads, they can be lightly steamed, boiled or stir-fried. Jicama is known to be a good source of potassium and vitamin C, this probably applies also to ahipa. In common with many legumes seed needs to be cooked to remove toxins.

Disadvantages: More of a vegetable than a food staple. Tubers have a low level of protein.

Siberian pea tree – Caragana arborescens
The Siberian pea tree is a fast growing undemanding deciduous shrub that usually grows to about 3 metres tall. The seeds are similar in size to lentils and can be used cooked in the same way, harvests begin after 5 to 8 years. They are up to 36% protein. This plant has great potential as an edible crop and nitrogen-fixer for use in temperate agroforestry and forest gardening, especially in dryer continental climates.

Prairie mimosa, Illinois bundleweed – Desmanthus illinoensis
A frost hardy North American perennial legume. The Land Institute in Kansas is evaluating it as an edible legume for growing with perennial grains in a no tillage system.

Disadvantages: Possible unpleasant aftertaste. Shattering seedpods.

Kudzu – Pueraria montana lobata
Kudzu has long been cultivated as staple food in Japan and China. The roots are up to 1.5 metres long, starchy and rich in carbohydrates. A very nutritious and versatile food, they can be eaten cooked, made into noodles, used in soups or as a thickener. They are rich in iron, calcium, potassium and zinc, dried root powder measures 21.8% protein. The plant has a very extensive root system and is useful for erosion control. Can be grown in cooler regions where top growth is killed by winter frosts.

Disadvantages: This plant illustrates the care that should be taken introducing non-native perennials. A shade tolerant extremely vigourous plant that has become an infamous weed in warm climates, especially the Southern USA, where it spreads quickly and is almost impossible to eradicate.

E-mail this article

bookmark this page

Printer-friendly version