Melilotus indicus Seeds | Indian Sweetclover
LATIN NAME: Melilotus indicus
COMMON NAME: Indian Sweetclover
Plant Profile
Melilotus indicus is a slender annual clover with a spike of tiny yellow pea flowers and a smell of new-mown hay that is stronger than its size suggests. It grows to about sixty centimetres, often leaning, with trifoliate leaves and a taproot that goes down further than the top growth suggests. It seeds heavily and dies after flowering.
The species is native to the Mediterranean and to the Indian subcontinent and is now a weed of roadsides, waste ground and field edges across the world. It is one of several sweetclovers used for fodder and for green manure, and it is also a common bee plant in the dry margins of farmland.
Science & Biotechnology
The hay smell comes from coumarin, which is present in the leaf and in the stem and which is released when the tissue is damaged. In damp hay the coumarin is converted by moulds into dicoumarol, an anticoagulant that caused fatal bleeding in cattle before the mechanism was understood, and that led to the development of warfarin. Sweetclover hay that has heated in the stack is therefore dangerous.
The plant is a legume and fixes nitrogen, and it is deep-rooted enough to bring up minerals from the subsoil. It is also a useful bee forage, producing a pale honey with a strong flavour, and it self-sows so freely that it can become a nuisance in a seedbed.
Uses & Benefits
The plant is used as fodder, as green manure and as a bee forage, and it is cut for hay in dry regions where other legumes fail. The seed is used as a flavouring in some districts, and the dried flower is used in sachets and in potpourri for its scent.
In traditional medicine the herb was used as an anti-inflammatory and as a treatment for varicose veins, a use that led to the isolation of coumarin and to the anticoagulant drugs. The plant is not used in modern pharmacy, and the dried herb should not be eaten in quantity because of the coumarin content. The seed is also scattered on stored grain to keep weevils out, a use that relies on the same thymol-rich oil.
Growing from Seed
Seed germinates readily and needs scarification only if it is old. Sow in spring or autumn at 15 to 20 degrees, and seedlings appear in one to two weeks. The plant self-sows, so one flowering is enough.
The plant grows on poor, dry, alkaline soil and needs full sun. It is hardy to about minus ten and tolerates drought. In a garden, deadhead it before the seed sets unless it is wanted as a green manure, and do not feed hay made from it to livestock if it has heated in the stack. It also tolerates lime, which is unusual in a fodder legume.
Our Take
A modest yellow clover with a hay scent and a serious lesson in its chemistry: damp sweetclover hay can kill cattle.
Related Reading
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