Field Pennycress
Thlaspi arvense L.
Family: Brassicaceae, Mustard
Genus: Thlaspi
Other names: stinkweed
Nomenclature: arvense = in meadows
Nativity / Invasiveness: introduced plant, weed
Edible plant
Medicinal plant
Toxic plant

General: plant height: 10-50 cm tall. Growth habit: erect annual. Stems: simple to freely branched, leafy, hairless.

Leaves: mostly alternate, oblanceolate, 2-6 cm long, the lower strongly wavy-margined to almost lobed, with larger end lobe, narrowed to a short stalk. Leaves farther up becoming stalkless, with ear-shaped lobes at base. Basal leaves few, withering by flowering time.

Flowers: white, in open clusters on branches, with 4 petals 3-4 mm long and sepals 1.5-2.2 mm long. May-August.

Fruits: pods strongly flattened, oval or cordate, shallowly notched, 10-17 mm long, with winged edge all around, the notch 1.5-2.5 mm deep. Stalks slender, spreading to upcurved, 7-15 mm long. Style almost lacking, 0.1-0.2 mm long. Seeds about 2 mm long, not edged, wrinkled lengthwise.


Common weed on disturbed ground in all parts of MT. Introduced from Europe, now spread across N. America.
Edible Uses

Young leaves of field pennycress, raw or cooked, are edible. They should always be harvested before the plant comes into flower or they will be very bitter. Even the young leaves have a somewhat bitter flavor and aroma, and are not to everyone's taste. They can be added in small quantities to salads and other foods. They can also be cooked in soups or used as a potherb. They taste somewhat like mustard but with a hint of onion. The Cherokee Indians used them for food. Dried leaves reportedly contain 54% protein and 1900 mg of Vitamin C per 100 g. For a leaf, it is very rich in protein.

Medicinal Uses

The seed is a tonic. Both the seed and the young shoots are said to be good for the eyes. The seeds are used in Tibetan medicine and are considered to have an acrid taste and a cooling potency. They are anti-inflammatory and fever-reducing, being used in the treatment of pus in the lungs, renal inflammation, appendicitis, seminal and vaginal discharges. The entire plant is anti-inflammatory and acts as a blood tonic and blood purifier. It has agents that induces sweating, agents that induces the removal (coughing up) of mucous secretions from the lungs. It is fever-reducing and promotes the well-being of the liver and increases the secretion of bile. The plant is used in the treatment of carbuncles, acute appendicitis, intestinal abscess, post-partum pain, dysmenorrhea and endometriosis. It should be used with caution since large doses can cause a decrease in white blood cells, nausea and dizziness. Pennycress also has a broad antibacterial activity, effective against the growth of staphylococci and streptococci.

Toxic Properties

The plant contains sufficient quantities of glucosinolates to be toxic. During dry periods, cattle in western Canada have ingested hay containing high quantities of stinkweed. Poisoning, death and abortion occurred. Tests of stinkweed showed that the allylthiocyanate (a glucosinolate) content is sufficient to cause sickness and death in cattle. Fatalities occurred at about 65 mg/kg of body weight. The amount of this chemical varies with the stage of maturity of the plant, the highest amount is in the seeds. Cattle that ingested hay containing between 25-100% stinkweed were colicky and some abortions occurred. Ensiling hay containing stinkweed apparently prevented liberation of allylthiocyanate.

Other Uses

The seeds contain 20 - 30% of a semi-drying oil, which can be used for lighting.

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