Lupinus luteus
L.
Yellow Lupin, European yellow lupine
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(c) Jeremy Gilmore, some rights reserved (CC BY), uploaded by Jeremy Gilmore
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(c) Valter Jacinto, some rights reserved (CC BY-NC-SA)
Description
Lupinus luteus is a ANNUAL growing to 0.6 m (2ft) by 0.3 m (1ft in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 6. It is in flower from June to July, and the seeds ripen from August to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. The plant is self-fertile. It can fix Nitrogen. It is noted for attracting wildlife. Suitable for: light (sandy) and medium (loamy) soils and can grow in nutritionally poor soil. Suitable pH: mildly acid and neutral soils and can grow in very acid soils. It cannot grow in the shade. It prefers moist soil.
Edible Uses
Coffee. 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 by Von Sengbusch. The roasted seed is a coffee substitute.
Known Hazards
The seed of many lupin species contain bitter-tasting toxic alkaloids, though there are often sweet varieties within that species that are completely wholesome. Taste is a very clear indicator. These toxic alkaloids can be leeched out of the seed by soaking it overnight and discarding the soak water. It may also be necessary to change the water once during cooking. Fungal toxins also readily invade the crushed seed and can cause chronic illness.
Distribution
Europe - Italy and the Mediterranean.
Where It Grows
EUROPE: Spain (west), Portugal AFRICA: Algeria, Morocco, Tunisia
Cultivation
An easily grown plant, succeeding in any moderately good soil in a sunny position. Succeeds in poor soils. Requires an acid to neutral soil. Cultivated for its edible seed in Italy, there are a number of varieties with sweet tasting seeds. 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.
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.
Other Uses
Green manureA 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.
