Sinapis alba aka Yellow Mustard

Sinapis alba is an annual in the cabbage family, Brassicaceae. Its common names include white mustard, yellow mustard and salad mustard. Kew places its native range from Europe to China. The RHS also lists it as native to Britain and Ireland. It grows across lowland Britain, including fields and waste ground. Plants For A Future notes its presence on lime-rich soils.

The plant has a bushy form and deeply lobed leaves. It completes its growth cycle within a year. The RHS species description reports clusters of white, four-petalled flowers. These appear from late spring into summer. Birds, bees, caterpillars and other insects find food on the plant. This makes it useful in gardens managed for wildlife. Its seed also has food and crop uses.

Grow white mustard in full sun and fertile soil. It prefers moist ground that drains well. The RHS lists chalk, clay, loam and sand as suitable. It also accepts acid, neutral and alkaline soils. Its shallow roots limit growth during dry spells. Plants For A Future describes rapid growth from seed. Plants can make a large amount of leafy growth within weeks. The RHS gives it a UK hardiness rating of H4. Plants For A Future lists USDA zones 5–9.

Growers raise it for fodder, mustard seed and green manure. It needs no pruning, and propagation is by seed. Its seed oil has uses in lighting and lubrication. Flea beetles and caterpillars may damage the plants. Clubroot is another risk, as with other cabbage-family crops. This disease can limit its value as a green manure. Avoid that use where clubroot is already a concern.

The leaves can be eaten raw or cooked. Young leaves add a sharp taste to mixed salads. Older leaves serve as cooked greens. The seeds can be sprouted or ground for seasoning. White mustard tastes milder than black mustard, according to Plants For A Future. That source also records traditional medicinal uses, including mustard plasters. These uses do not remove the need for caution. Seed compounds can irritate skin and the linings of the body. Mustard can also cause allergic reactions. Plants For A Future warns of possible poisoning after seedpods form.