Common Name: Blue Lupin

General Information

Lupinus angustifolius is an erect annual plant growing 20 - 150cm tall[].
The plant is harvested from the wild, and sometimes cultivated, for its edible seed. It is also grown as a green manure (especially in Mediterranean climates) in order to enrich the soil, and is often used as an ornamental in the garden.
Lupinus angustifolius is a widespread species that occurs in a variety of habitats with no major threats. However, it has been suggested that viable habitats are in decline due to the increasing human population and over-grazing of farm animals. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

Lupinus species in general (and especially the seeds) contain a range of bitter-tasting alkaloids such as lupine, anagyrine, sparteine and hydroxylupanine. The pharmacological effects of these alkaloids are that they block ganglionic transmission, decrease cardiac contractility and contract uterine smooth muscle[]. When ingested in moderate to large quantities they can cause symptoms such as respiratory depression and slow heartbeat, sleepiness and convulsions[].
Alkaloid levels can vary greatly from species to species, and this species is considered to be one of the more toxic. However, low-alkaloid, sweeter-tasting varieties have been developed that are cultivated as a food crop. There are also techniques (particularly soaking and discarding the soak water) that lower the alkaloid levels.
Unless it is known that the plant is low in alkaloids then caution should be applied to any ingestion of the plant[].
Fungal toxins can readily invade the crushed seed and can cause chronic illness[].

Botanical References

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Range

Mediterranean region - Portugal to Bulgaria and Greece; Morocco, Algeria, Egypt; Turkey to Israel

Habitat

Cultivated and rocky ground on light acid soils45, ]. Roadsides, degraded shrubland, abandoned fields and shrub steppe, as well as in meadows, amongst rocks and bushes, and on sandy seashores; at elevations up to 1,500 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Habit	Annual
Height	1.00 m
Pollinators	Bees
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Lupinus angustifolius is a plant of the Mediterranean region, where it is found at elevations up to 1,500 metres. It can be cultivated as a summer annual in temperate regions, and is sometimes cultivated at higher elevations in the tropics (from 1,500 - 2,500 metres)[]. It grows best in areas where annual daytime temperatures are within the range 12 - 18°c, but can tolerate 4 - 26°c[]. It can tolerate occasional drops in temperature down to around -6°c[]. It prefers a mean annual rainfall in the range 400 - 1,000mm, but tolerates 350 - 1,700mm[].
Requires a sunny position[]. An easily grown plant, it prefers a light, acid soil but succeeds in any moderately good, well-drained soil[, , ]. Plants are tolerant of adverse conditions. Dislikes calcareous soils[]. Prefers a pH in the range 5.5 - 7, tolerating 4.9 - 8.2[].
Lupinus angustifolius is often cultivated, mainly as a green manure, in regions with a Mediterranean climate and is sometimes grown in other regions. It used to be a common green manure in America, but has rather fallen into disuse there[].
There are some named varieties that have been developed for seed consumption which are low in the bitter toxic alkaloids. 'Uniwhite' is a low-alkaloid variety with a permeable seed coat. It has reduced pod-shattering[] and so is easier to harvest mechanically.
Plants commence flowering around 80 - 120 days after sowing, with seeds maturing in 105 - 150 days[].
Yields of the seeds vary from as low as 290 kilos per hectare in parts of Africa to up to 4.5 tonnes in Australia[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[]. When removing plant remains at the end of the growing season, it is best to only remove the aerial parts of the plant, leaving the roots in the ground to decay and release their nitrogen.

Edible Uses

Seed - cooked[]. Used as a protein-rich vegetable or savoury dish in any of the ways that cooked beans are used, they can also be roasted or ground into a powder. If the seed is bitter this is due to the presence of toxic alkaloids and the seed should be thoroughly leached before being cooked. The seeds of low-alkaloid varieties is used in making 'tempeh'[]. The seed is rich in protein, though it is deficient in the amino-acid methionine[]. The protein has a high digestibility (90%) and biological value(53%)[].

Medicinal

None known

Agroforestry Uses:

A good green manure plant, it produces a good bulk of organic matter and fixes atmospheric nitrogen[]. It also makes phosphorus in the soil more available to other plants[].
The flowers are a good source of nectar for bees[].

Other Uses

Wild forms of Lupinus angustifolius have the potential for use as gene donors in crop improvement programmes for the various cultivated forms, especially in conferring anthracnose resistance and fusarium wilt disease resistance which are of particular commercial interest[].

A hydrolyzed extract of the seed is used as an ingredient in commercial cosmetic preparations as a hair and skin conditioner[].

The water used to leach alkaloids from the seeds of bitter forms of this plant is rich in alkaloids and can be used as an insecticide[].

Propagation

Pre-soak the seed for 24 hours in warm water and sow in mid spring in situ[, ]. You may need to protect the seed from mice. Germination should take place within 2 weeks.
The seed can also be sown in situ as late as early summer as a green manure crop.