Field Pennycress Greens

Native to Eurasia and now widely naturalized across the Northern Hemisphere.

• Originated in Europe and western Asia, spread globally with agriculture
• Present across all of Europe, northern Asia, and introduced throughout North America
• Known from archaeological sites in Europe dating back to the Neolithic period
• Traditionally used as a potherb and salad green in rural European communities
• Its widespread distribution as a weed of grain fields is documented in agricultural literature since Roman times

Thlaspi arvense is an erect, glabrous annual herb.

Stems:
• Erect, unbranched or sparsely branched, 20 to 80 cm tall
• Smooth, glaucous, often with a whitish bloom

Leaves:
• Basal leaves form a rosette, oblanceolate, petiolate, 2 to 8 cm long
• Stem leaves alternate, oblong to ovate, sessile with clasping, arrow-shaped bases
• Blue-green, smooth, slightly fleshy
• Strong garlic-mustard aroma when crushed

Flowers:
• Small, white, four-petaled, 4 to 6 mm across
• Dense terminal racemes that elongate in fruit
• Blooms spring through early summer

Fruits:
• Distinctive flattened, circular to broadly ovate silicles, 1 to 1.5 cm wide
• Resemble coins (hence "pennycress"), with a prominent notch at the tip
• Each pod contains 5 to 16 small brown to black seeds

Thlaspi arvense is an annual brassica with dual ecological identity as a common agricultural weed and a promising oilseed biofuel crop.

Habitat:
• Native to Eurasia — found across all of Europe, northern Asia, and Siberia
• Widely naturalized throughout North America since colonial times
• Found in cultivated fields, roadsides, waste areas, and disturbed ground
• Found at elevations from sea level to approximately 2,500 meters
• Adaptable to a wide range of soil types; prefers nutrient-rich agricultural soils
• USDA zones 3–10 (extremely wide range as an annual)

Growth Habit:
• Erect, glabrous annual herb growing 20 to 80 cm tall
• Fast-growing winter or summer annual — can germinate in autumn and overwinter as a rosette, or germinate in spring
• Strong taproot penetrates compacted agricultural soils
• Full sun requirement — thrives in open, cultivated habitats
• Distinctive flat, coin-shaped seed pods (pennycress) are unmistakable in the field

Pollination:
• Small white flowers are primarily self-pollinating, ensuring seed production without pollinators
• Also visited by small flies and bees for supplemental cross-pollination
• Produces abundant seed — a single large plant can produce 15,000 to 20,000 seeds
• Seeds can persist in the soil seed bank for up to 20 years, creating a long-term seed reservoir

Ecological Role:
• Known from archaeological sites dating to the Neolithic period — has been associated with human agriculture for over 6,000 years
• The garlic-mustard flavored leaves and seeds contain glucosinolates that deter generalist herbivores
• Flat seed pods are distinctive and easily dispersed by wind and water
• Serves as a host plant for various brassica pests including flea beetles and diamondback moth
• Being actively researched as a winter cover crop and oilseed biofuel feedstock — its high seed oil content (30 to 36%) makes it promising for renewable jet fuel production

Invasive Status:
• Common agricultural weed throughout the Northern Hemisphere but not listed as noxious in most jurisdictions
• Can reduce crop yields in grain fields but is generally controlled by standard herbicide practices
• Its potential as a cultivated oilseed crop may transform its status from weed to crop

Young leaves are nutritious when consumed in moderation.

• Good source of vitamins A and C
• Contains iron, calcium, and potassium
• Seeds contain 30 to 36% oil rich in erucic acid and oleic acid
• High protein content in seeds (approximately 25%)
• Glucosinolate content should be noted — moderate consumption is recommended
• Seeds are being developed as a source of renewable jet fuel and biodiesel

Grows readily from seed and is rarely deliberately cultivated for greens, though research plots exist for oilseed production.

• Sow seeds in early spring or autumn directly where they are to grow
• Extremely adaptable — tolerates poor soils, compaction, and a wide pH range (5.0 to 8.0)
• Prefers full sun but tolerates partial shade
• Cold-hardy and frost-tolerant, often germinating in late autumn and overwintering as a rosette
• Harvest young basal rosette leaves in early spring before flowering
• Requires no fertilizer or irrigation under normal field conditions

Culinary uses:
• Young leaves eaten raw in salads for a sharp, garlicky-mustard flavor
• Cooked as a potherb — added to soups and stews where heat mellows the pungency
• Used sparingly as a flavoring herb in marinades and dressings
• Seeds can be ground as a mustard-like spice
• Research is underway to develop pennycress as a commercial oilseed crop for cooking oil and biofuel
• Young plants can be fermented into a tangy sauerkraut-style preserve