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Weed Identification

Virginia Tech College of Agriculture and Life Science Virginia Cooperative Extension

wild mustard

Family

Brassicaceae

Scientific Name

Brassica kaber
Weed photograph 1
Weed photograph 2
Weed photograph 3
Weed photograph 4
Weed photograph 5
Weed photograph 6
Weed photograph 7

Other Common Names:

canola
charlock mustard
kaber mustard
rapeseed

Synonyms (former Scientific Names):

Brassica kaber
Brassica arvensis

Habit

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

Leaves

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

dime

Dominant Flower Color

yellow

Flower Symmetry

radial symmetery

Leaf Hairs

has hairs

Leaf Shape

triangle

Leaf Arrangement

alternate

Leaf Margin

serrated

Leaf Structure

simple

Leaf Stalk

shorter than leaf

Stem Hairs

Varies: 
has hairs, 
no hairs

Stem Cross Section

round or oval

Milky Sap

not present

Root Structure

Varies: 
fibrous, 
taproot

Life Cycle

winter annual

Plant Type

Herb