American Wintercress

American Wintercress © DSchiel

American Rocket, American Yellowrocket
Barbarea orthoceras

Description (Jepson,

  • Eudicotyledon
    • Eudicots are a major lineage of flowering plants; see family for general characteristics
  • Mustard Family (Brassicaceae)
  • Perennial herb
  • Stems are erect, with ridges
  • Leaves
    • Form a basal rosette and occur along the stem, reducing upward
      • Each leaf is divided into 1-4 leaflet pairs (pinnately compound), with a larger terminal leaflet
      • Leaflets may be wavy edged and sparsely toothed
    • Stem (cauline) leaves attach directly to the stem (sessile)
  • Flowers
    • Inflorescence (flower arrangement) is a raceme (unbranched stem with stalked flowers opening from the bottom up)
    • Each flower with 4 yellow petals forming a cross
    • 6 stamens (male flower parts), 4 long and 2 short
    • Sepals (outer flower parts) yellow to yellow green
    • Ovary superior (above the attachment of other flower parts)
  • Fruit is an upright silique (long, narrow pod) with a horn-shaped tip
  • Height to 20 in.
Flowers © DSchiel


  • Native to California
    • Grows predominately in moist areas
    • See Calflora for statewide observations of this plant
  • Outside California, grows in Western North America, and in parts of central and eastern Asia
  • Grows at elevations to 11,000 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

  • Wildlife
    • Visited by flies, bees, and beetles
    • Larval food source (host) for several butterfly species, e.g. Sara orangetip (Anthocharis sara) and checkered white (Pontia protodice)
  • Human
    • Leaves can be eaten raw or cooked

Name Derivation

  • Barbarea (bar-BARE-ee-a) – named after St. Barbara, a 3rd-century Greek Christian martyr
  • orthoceras (or-tho-SER-as) – from the Greek órthios, “straight, upright” and kéras, “horn,” referring to the horn-tipped fruit
  • Wintercress – common name for plants in this genus
    • Cress is a name associated with cruciferous plants (Mustard family)
  • Rocket – common name for many plants in the Mustard family
    • From the Italian ruchetta or rucola, a diminutive of the Latin eruca, once a name for a kind of mustard plant and now a genus in the Mustard family, which includes the leafy vegetable arugula or rocket (Eruca vesicaria)


  • Crushed plant tissue of most Mustard species release peppery-smelling, pungent-tasting isothiocyanates (cyanide compounds), derived from glucosinolates (Ishida 2014); see Mustard family for more details

ID Tips

  • May be confused at Edgewood with 2 yellow-flowering, non-native mustards — short-podded mustard (Hirschfeldia incana) and hedge mustard (Sisymbrium officinale)
American WintercressHedge MustardShort-podded Mustard
Growth Habitperennial herbannual herbperennial herb
Height≤ 20 in.≤ 24 in.≤ 31 in.
Hairy Stemnosometimesyes
Basal Leaf Terminal Lobebroad-rounded tipacutely-pointed tipbroad-rounded tip
Flower Stalkerect, compact laterally sprawling laterally sprawling 
Fruitnot appressed to stemappressed to stemappressed to stem
Habitatwoodlanddisturbed areasdisturbed areas

At Edgewood

  • Found in woodlands
  • Flowers March – July

See General References

Specific References

Ishida, M., et al. 2014. Glucosinolate metabolism, functionality and breeding for the improvement of Brassicaceae vegetables. Breeding science, 64: 48–59. J-STAGE.