Common Name: Yellow Lupin

General Information

Lupinus luteus is an annual plant growing 25 - 80cm tall[].
The plant is sometimes harvested from the wild for local use as a food. Low-alkaloid varieties have been developed that are sometimes grown for their edible seeds, whilst the plant is also grown as a green manure in order to improve the soil and is commonly grown as an ornamental in gardens.
Lupinus luteus is a widespread, common species found in disturbed habitats, and has no major threats. 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, Spain, possibly also native in Italy, Morocco, Algeria, Tunisia, Israel and Jordan

Habitat

Light acid soils[]. Degraded scrub lands, abandoned fields, road sides, on neutral or decarbonated and acidic soils, and sandy loam soils; at elevations up to 1,100 metres[]..

Properties

Conservation Status	Least Concern
Edibility Rating
Other Uses Rating
Habit	Annual
Height	0.60 m
Pollinators	Bees
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Lupinus luteus is a plant of the Mediterranean region, where it is found at elevations up to 1,100 metres. It is cultivated in much of the temperate zone, and can also be cultivated at higher elevations (from 2,000 - 3,300 metres) in the tropics It grows best in areas where annual daytime temperatures are within the range 18 - 24°c, but can tolerate 6 - 30°c[]. The plant can survive occasional temperatures down to about -3°c. It prefers a mean annual rainfall in the range 450 - 1,000mm, but tolerates 350 - 2,100mm[].
Requires a sunny position[]. An easily grown plant, succeeding in any moderately good, well-drained soil[, ]. Succeeds in poor soils[]. Found mainly on acidic, sandy soils in the wild, the plant is highly susceptible to iron and manganese deficiencies when growing on neutral and calcareous soils[]. Tolerant of short periods of soil inundation[]. Prefers a pH in the range 5.5 - 7, tolerating 4.5 - 8[].
Often grown as an ornamental and green manure, the plant is also sometimes cultivated for its edible seed, mainly in parts of Europe[, ]. There are a number of cultivars that have been developed with low-alkaloid, sweet tasting, larger and soft-skinned seeds in non-shattering seedpods[, ].
Plants commence flowering around 100 - 115 days after sowing, with seeds maturing in 100 - 135 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[].
The flowers have a delicious vanilla-like perfume, the cultivar 'Romulus' has been especially mentioned[].
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. The seed can also be ground into a powder and be mixed with cereal flours for making bread etc[]. If the seed is bitter this is due to the presence of toxic alkaloids and the seed should not be eaten without treatment[]. These alkaloids can usually be removed by soaking the seed in 2 or 3 changes of water. Low alkaloid varieties were developed prior to 1930[].

The roasted seed is a coffee substitute[].

Young leafy tops - cooked and eaten as a vegetable[].

Medicinal

None known

Agroforestry Uses:

A good green manure for poor soils, it is quite fast growing and fixes atmospheric nitrogen[, , ]. It is commonly grown as a soil improver in southern Europe[].
The plant is a good source of nectar for bees[].

Other Uses

The wild species belongs to the primary Gene Pool of cultivated Yellow Lupin (Lupinus luteus) and to the secondary Gene Pool of Blue Lupin (Lupinus angustifolius), and so it has the potential for use as a gene donor for crop improvement[].

An extract of the seed is used as an ingredient in commercial cosmetic preparations as a masking agent 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.