Black mustard is native to tropical North Africa,
temperate regions of Europe, and parts of Asia. It is naturalized throughout most of North America.
Black mustard prefers disturbed soils, river or stream floodplains, lake shores, and meadows and
The plant contains glucosinolates,
chemicals that deter herbivores.
Plants: 24-96" (60-243 cm) tall, branching sometimes.
Stems are smooth near the top, become sparsely to densely hairy near the base. They are covered with a waxy substance that rubs off easily.
Leaves: alternate, up to 10" (25 cm) long ×
3" (7.6 cm) wide, on long stalks (petioles). They are deeply divided.
Flowers: Yellow, with four petals, in clusters at stem
tips. Each petal is ¼-⅜" (7-11 mm) long and ¹/₁₆-⅛" (3-4 mm) wide.
Fruits: Long narrow upward-pointing seedpods are ⅜-⅞" (1-2.5 cm)
in length. Each seedpod contains
four rounded black or brown seeds.
Edibility: Black or dark brown seeds are commonly
used, after removing seed coats and grinding, as a curry spice or similar flavoring agent.
Medical: Mustard or other pastes made from the seeds
were once used to treat respiratory ailments or relieve muscular pains.