Family: Brassicaceae
Origin, Description & Uses:
Thlaspi arvense, commonly known as bastard cress or field pennycress, is an annual herb native to Europe and Asia but now found in many temperate regions worldwide. It is a fast-growing plant in the mustard family (Brassicaceae), typically recognized by its small white flowers and distinctive flat, round seed pods that resemble coins. Field pennycress thrives in disturbed soils such as roadsides, agricultural fields, and waste areas. It has been explored for use as a cover crop to reduce soil erosion, improve soil health, and suppress weeds. Additionally, its seeds are being studied as a potential source of biofuel oil, and the plant has some limited historical uses in traditional herbal practices.
Risks & Threats:
Although field pennycress is not currently known to be naturalized in the Hawaiian Islands, it possesses traits that are cause for concern. This species grows rapidly, produces abundant seeds, and can easily spread in disturbed environments—characteristics that increase its potential to become invasive. In tropical island ecosystems like Hawaiʻi, such aggressive growth could allow it to outcompete native plants, alter soil conditions, and disrupt fragile ecological balances. Its ability to establish quickly in agricultural and open areas also raises concerns for local farming systems. Because of these risks, it is recommended to avoid introducing or planting this species and instead choose a low-risk or native alternative better suited to protecting Hawaiʻi’s unique ecosystems.
High Risk Traits:
- Native to tropical regions
- Wide environmental tolerance
- Widely naturalized
- Disturbance weed
- Agricultural weed
- Toxic to animals
- Tolerant of wide variety of soil conditions
- Persistent seed bank
- Self-compatible
- Short reproductive time
- Crop contaminant
- Dispersed by wind, animals, water, accidentally
- Prolific seeder
- Herbicide resistant
Low Risk Traits:
- Not parasitic
- Non-toxic to humans
- Shade intolerant
- Not a nitrogen-fixer
