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 ridged or angled
    • Leaves
      • Basal rosette leaves
        • Pinnately compound (divided into leaflets arranged along a common axis, like a feather)
        • Leaflets in 2-4 pairs, ending in a large, rounded lobe
        • Wavy edged and sparsely toothed
      • Stem leaves
        • Alternate (1 leaf at each junction with stem)
        • Pinnately lobed or divided, with 1-2 leaflet pairs, reducing upward
        • Widely spaced and directly attached to the stem (sessile)
        • Sometimes wavy edged and sparsely toothed
    • 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 (attached above 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)

        • Visited by flies, bees, and beetles
        • Host plant for the larvae of several butterfly species, including Sara orangetip (Anthocharis sara) and checkered white (Pontia protodice)
        • 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, 64:1, pp. 48–59.