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Weed Identification

wild mustard



Scientific Name

Brassica kaber

Other Common Names:

charlock mustard
kaber mustard

Synonyms (former Scientific Names):

Brassica arvensis
Brassica kaber


Most often a winter annual but sometimes a summer annual with characteristic yellow mustard flowers


Alternate, egg-shaped to ovate in outline, approximately 2 to 8 inches long and 1/2 to 1 1/2 in wide. Lower leaves occur as a rosette, are petiolated, and unevenly lobed with toothed margins. Upper leaves become progressively smaller up the stem, are not lobed, and either clasp the stem or have short petioles.

Identifying Characteristics

Erect, branched towards the top of the plant and usually have hairs at least at the base of the plant but hairs can also be absent. Generally, a plant with a winter growth habit that has typical yellow mustard flowers and irregularly lobed leaves with wavy margins toward the base of the plant and much smaller, unlobed leaves at the top of the plant. At maturity the flowers of several mustard species, including Yellow Rocket (Barbarea vulgaris) and Wild Radish (Raphanus raphanistrum), resemble those of wild mustard. However, wild radish has leaves that are covered with stiff hairs unlike either wild mustard or yellow rocket. Additionally, the large terminal lobe in the leaves of yellow rocket helps to distinguish this weed from wild mustard.

Flower Seed Head

Produced in clusters at the ends of branches. Individual flowers consist of 4 yellow petals and are approximately 3/4 inch wide.

Seed Fruit

A silique that is approximately 1 to 2 inches long and 2 to 3 mm wide. Siliques occur on flower stalks that are approximately 5 to 7 mm long and are rounded in cross-section but have a 4-angled flattened beak at the tip that is a little less than half as long as the pod.

Where Found

This weed can be found throughout the United States primarily in nurseries and winter small grains.

Growth Habit

upright and nonwoody

Thorns or Spines

not present

Approximate Flower Diameter


Dominant Flower Color


Flower Symmetry

radial symmetery

Leaf Hairs

has hairs

Leaf Shape


Leaf Arrangement


Leaf Margin


Leaf Structure


Leaf Stalk

shorter than leaf

Stem Hairs

has hairs
no hairs

Stem Cross Section

round or oval

Milky Sap

not present

Root Structure


Life Cycle

winter annual

Plant Type