Field Pennycress
Family: Brassicaceae - Genus: Thlaspi - Species: T. arvense
Other names: Frenchweed, Stinkweed
Quick facts
- Uses
- Soil builder
- Edible parts
- None
- Type
- annual herb
- Flowers
- Mar–Nov
- Height
- 30–60 cm
- Native to
- Europe and Asia
- Habitat
- fields, roadsides, disturbed areas
| Month | Observations |
|---|---|
| January | 5 |
| February | 17 |
| March | 200 |
| April | 416 |
| May | 545 |
| June | 183 |
| July | 58 |
| August | 16 |
| September | 16 |
| October | 17 |
| November | 87 |
| December | 22 |
Field pennycress is a common weed of grain fields and roadsides. Crush it and you'll understand its other name, "stinkweed": it smells strongly of garlic.
Its seed pods are the best part. They're round, flat and papery, like little coins, and they shine in the sun as they dry.
How to spot it
- Leaves on the stem are long and toothed, and they clasp the stem with two small ear-like lobes.
- Flowers are small and white, with four petals, in a cluster at the top of the stem.
- Seed pods are round and flat, about 1 cm across, with a notch at the top.
- The smell is garlicky when you crush any part of the plant.
What it's good for
Farmers are starting to take this weed seriously. Plant breeders are developing pennycress as a winter cover crop, because it protects the soil over winter and its oily seeds can be made into biofuel.
The young leaves are edible but very bitter, so few people eat them. Some of its close relatives can absorb heavy metals from polluted soil, and scientists study them as a way to clean up contaminated land.
Gallery
Stem with round, flat seed pods
Where it grows
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Each hexagon shows how many times Field Pennycress has been recorded there, from herbarium specimens, surveys and iNaturalist photos. Gaps can mean nobody has looked, not that the plant is absent.