Plants germinate or sprout in fall, are green during the winter,
and produce flowers and seed in the spring and early summer.
Plants usually die back with summer heat. The stems are erect, 1
m tall, branched, hairy, and usually bluish-green in color.
Leaves are light to medium green, hairy or bristly, stalked, and
are 30–50 cm long. Like most mustards, leaves tend to feel rough
due to the stiff hairs on the leaf surface. Leaves are often
ravaged by insects and often appear with holes or eaten portions
missing. The flowers have four petals that form a cross. Flower
Seed Head: Flowers bright yellow; petals 6–10 mm long; those in
maturity close together and commonly overtop the unopened buds;
outer 2 stamens are much shorter than inner stamens. Fruit is
4–6.5 cm long with long tapering beak. Seeds are blackish or
reddish-brown and 1.5–2 mm in diameter. Found along roadsides
and waste areas. A common weed of agricultural fields.