Field pennycress is a winter annual, and it is easiest to stop in the fall, which is why we’re talking about it this month.
A member of the mustard family, field pennycress starts out as a rosette in the fall with club-shaped leaves. When it bolts in the spring and grows taller, its flowers are small and white with four petals. Field pennycress has a distinct, garlic-like odor, so if dairy animals consume it, the odor from the pennycress can also be found in the milk. Therefore, pennycress control in grasslands and alfalfa is especially important. Since it is a winter annual weed, pennycress gets a fast start in the spring and can easily overtake fields, creating a difficult burndown or tillage situation.