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Ministry of Agriculture, Food and Rural Affairs

Mustards - Wild or Wormseed

There are 2 types of mustards common throughout Ontario: wild and wormseed.

Scientific Names: Wild mustard, Sinapis arvensis L.; Wormseed mustard, Erysimum cheiranthoides L.

Other Names

Wild Mustard Wormseed Mustard
  • Common mustard
  • Moutarde des champs
  • Charlock
  • Field mustard
  • Herrick
  • Kale
  • Mustard
  • Yellow mustard
  • Moutarde sauvage
  • Sénevé
  • Brassica kaber
  • Vélar fausse giroflée
  • Treacle mustard
  • Vélar giroflée

Family: Mustard family (Cruciferae)

General Description: Annuals, or winter annual for wormseed, reproducing only by seed

Habitat: Both mustards occur throughout Ontario. Wild mustard is most frequent in cultivated fields and gardens, occasionally appearing in fence lines, along roadsides and in waste areas. Wormseed mustard grows in a very wide variety of habitats from dry, rocky, shallow soils to moist sandy shores, to rich loam and clays and is found in grain fields, hay and pastureland, waste places, gardens, poorly kept lawns, roadsides and railways, riversides, sandy beaches and limestone talus.


Wild Mustard Wormseed Mustard


Wild Mustard Wormseed Mustard
  • Erect
  • 20- 90 cm (8- 36 in.) high
  • Branching in the upper part
  • Harshly hairy near the base but weakly hairy or smooth upwards
  • Greenish or sometimes purplish
  • Erect
  • 15- 100 cm (6- 40 in.) high
  • Usually branched
  • Apparently hairless but slightly rough due to tiny flat-lying, 2-branched hairs


Wild Mustard Wormseed Mustard
  • Alternate (1 per node)
  • Somewhat hairy
  • Lowermost leaves on young plants long-stalked and either without lobes or with shallow to deep lobes near the base of the blade
  • Upper leaves stalkless and coarsely toothed; usually not lobed
  • Alternate (1 per node)
  • Slightly rough on both surfaces with tiny 3-branched hairs
  • Nearly linear or broader near the middle and tapering to both ends
  • Without teeth or with a few wavy or slightly pointed teeth


Wild Mustard Wormseed Mustard
  • In small clusters which lengthen as the seedpods develop
  • Bright lemon yellow
  • 1.5 cm (3/5 in.) across
  • 4 small sepals
  • 4 larger petals arranged in the form of a cross
  • 4 long and 2 short stamens
  • 1 slender pistil
  • Flower stalks thin and short (3- 5 mm, 1/8- 1/5 in. long), becoming thicker but not longer as the seedpods develop, sometimes nearly as thick as the pod itself
  • Seedpods:
    • 3- 5 cm (1 ¼- 2 in.) long
    • Sometimes bristly hairy but usually without hair
    • Often with lengthwise ribs
    • Erect and pressed to the stem or spreading out
    • Each pod with a flattened terminal beak
    • 1 or rarely 2 seeds in its base; several seeds in its main section
  • Seeds:
    1.5 mm (1/16 in.) in diameter
    Black or purplish
  • Flowering may begin as early as late May and continue throughout the summer
  • Crowded in clusters at the ends of the stems and branches, these lengthening as the pods develop
  • Paler yellow
  • 6 mm (1/4 in.) across
  • Similar to wild mustard
  • Seedpods:
    • 15- 25 mm (3/5- 1 in.) long
    • On slender stalks about 1 cm (2/5 in.) long which stand out from the stem
    • The pod itself standing upwards or nearly parallel to the stem
    • Usually somewhat 4-angled in cross-section
    • Tipped by a short blunt beak
  • Seeds:
    • About 1 mm (1/25 in.) long, half as wide
    • Dull reddish-yellow
  • Flowers from mid-June to late autumn and sheds mature seeds soon after flowering

Often Confused With
Yellow Rocket (Wild Mustard is distinguished from Yellow rocket by being annual with hairy stems, its lemon-yellow flowers usually not appearing before late May and its seedpods on short, thick stalks and having a prominent, flat beak containing 1 or 2 seeds)

Mustard seedling Mustard Mustard in flower Wild mustard in flower Wormseed mustard
Click to enlarge.