Common Name: White Melilot

General Information

Melilotus albus is an annual to biennial plant growing from a deep taproot. A single, erect to ascending, well-branched stem is produced in the first year, with up to 10 stems being produced in the second year of growth; the plant can grow up to 150cm tall[, , ].
The plant is harvested from the wild for local use as a food, medicine and source of materials. It is cultivated as a green manure crop and soil improver and is sometimes grown as an ornamental and medicinal plant[].
Melilotus albus has typical weedy attributes such as prolific seed production, persistence and presence along roadsides and railways, and as a result can negatively impact ecosystem services, wildlife habitats, and agriculture. Although the plant can be a problematic invasive species it is also important in many places as a fodder crop, a bee plant for honey production, soil stabiliser and a useful species for land reclamation[]

Known Hazards

The plant contains coumarin, a substance produced by the plant because it acts as an appetite suppressant and gives some protection from grazing - it is also the compound that gives some dried plants the smell of new mown hay. Coumarin is found naturally in many fruits, including strawberries, black currants, apricots, and cherries; it also has some medicinal applications, though it is also known to be toxic, affecting especially the liver and kidneys. Coumarin is of relatively low toxicity to humans – indeed it has often been used as a flavouring and aromatic additive in foods and other commodities. However, it can be much more toxic to other species, especially rodents and specifically rats.
The fresh plant material, consumed in moderation, is generally safe. However, the dried plant material, especially if it is not dried properly and is invaded by fungi, is potentially much more toxic as the coumarin breaks down to form other compounds that can have a strongly anticoagulant effect upon the blood. Warfarin, a well-known anticoagulant drug and rat poison, is one of those compounds produced from coumarin.

Botanical References

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Range

Eurasia - Finland to Spain, east through Russia and Greece to W. Siberia, C. Asia, the Himalayas and Arabia; N. Africa - Libya, Egypt

Habitat

Fields and waste places on dry, not acid soils[]. A plant of open, disturbed places, being found in sites such as sand dunes, prairies, desert scrub, roadsides etc, but avoiding the dryest areas[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual/Biennial
Height	1.20 m
Growth Rate	Fast
Pollinators	Bees, Insects, Self
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Melilotus albus is a plant of the temperate zone, where it is found at elevations up to 1,500 metres. It grows best in areas where annual daytime temperatures are within the range 12 - 28°c, but can tolerate 8 - 32°c[]. When dormant, the plant can survive temperatures down to about -30°c, but young growth is more tender and can be severely damaged at -1°c[]. It prefers a mean annual rainfall in the range 600 - 800mm, but tolerates 425 - 1,000mm[].
Requires a sunny position[] Succeeds on a wide range of soil types so long as they are well-drained[]. It grows well in alkaline and moderately saline conditions, but dislikes acid conditions[]. Prefers a pH in the range 6.5 - 7.5, tolerating 6 - 8[]. Established plants are drought tolerant[].
Cultivated as a medicinal plant, green manure and soil improver, some named forms have been developed[].
A fast growing plant[].
The dried plant has a sweet smell of newly mown hay[].
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[].

Edible Uses

Leaves and seedpods - cooked as a 'bean soup'[, , ].
Young shoots - raw or cooked[, ]. Added to salads or used as a potherb[].

The pea-like seeds are used as a seasoning for bean and split-pea soups[].

Flowers - raw or cooked[]. Used as a vanilla-like flavouring[, ].

The dried leaves are said to be used as a vanilla flavouring[] but this is probably unwise, see notes at top of the page.

Medicinal

The whole herb, harvested when in flower, is aromatic, carminative and emollient[]. It was at one time widely esteemed as a medicinal herb, though it has fallen from favour in recent times[].

The dried leaves contain coumarin, this can be used as an anticlotting agent for the blood[]. The coumarin found in plants does not have anticoaggulant activity, it is the various compounds derived from coumarin that are used in this way. Simply drying the plant will not necessarily produce these compounds[].

The dried flowering plant has been used in ointments for external ulcers[].

Agroforestry Uses:

Melilotus albus is one of the best legumes for soil improvement, with widely-branched, deeply-penetrating tap roots that open up the subsoil. The roots use nutrients not available to plants with shallow roots. When the plants decay, the nutrients in the roots are released for use by other crops[].
It can be sown in the autumn and overwintered or sown from spring to mid summer. It can be cut several times for compost material before being finally incorporated into the soil[, 87,172]. Fast growing, it produces a high bulk of organic material and also fixes a large quantity of atmospheric nitrogen[]. It can also be grown under soft and top fruit, when it will expel mice[].
The plant is an excellent source of nectar and pollen for honey bees[, , ].

Other Uses

An oil obtained from the seed is used in paints, varnishes etc[].

The dried leaves smell of new-mown hay and are used as an insect repellent[]. The dried leaves contain a substance called coumarin, this is an anti-clotting agent and has been used as a basis of the rat killer 'warfarin'[].

An extract of the flowers, leaves and stems is used as an ingredient in commercial cosmetic preparations as an antimicrobial and an antioxidant[].

Propagation

Seed - sow spring to mid-summer in situ[]. Pre-soaking the seed for 12 hours in warm water will speed up the germination process, particularly in dry weather[]. Germination will usually take place within 2 weeks. Seed can also be sown in the autumn and will flower the following spring to summer[].
The seed produced can have either hard or soft seedcoats. Soft-coatd seeds germinate quickly without treatment, but hard-coated seeds can remain dormant in the soil for several years before germinating. In cultivation, the hard-coated seed requires pre-soaking in warm water in order to soften the seedcoat[].