University of Maryland Extension

Weed of the Week - Lesser Seeded Bittercress

Chuck Schuster

Lesser-Seeded Bittercress, Cardamine oligosperma, seems to be abundant in the landscape currently. This is a newer weed in this area, and can be found in turf, landscape, in ground nursery and also container nursery production. Very similar to Hairy Bittercress, it is typically a summer annual, but can also be found in some locations as a fall germinating weed. Lesser- Seeded Bittercress, is part of the Mustard family, native to Eurasia, it now is found throughout the United States and is moving into this region. This weed will grow three to five inches in height, originate from a basal rosette, will have a taproot with dense fibrous hairs, the leaves will be lobed, opposite and the petiole will be without hairs. The flower of this weed will be in clusters at the end of flowering stems, will have four petals, narrow, and white in color. The fruit of this weed is a silique, a narrow capsule that is designed to release the seeds held within in an explosive manner, spreading the seed up to eight feet from the plant.

Control of this weed is difficult especially with having it germinate this time of year. Cooler temperatures can make post emergent control harder without the plant being in active growth. Hairy Bittercress control can be accomplished with the use of Pre-emergent products that include oxadiazon (Ronstar), flumioxazin (Broadstar) or isoxaben (Gallery). It is too late at this point to use pre-emergent products for what we see, post emergent products can provide excellent control in turf, they include, 2,4D and triclopyr (Chaser) Metsulfuron (Blade),  Speedzone  (tri-mec + Quicksilver ) works better in the cooler weather so it can be a useful tool now. These products should provide ninety percent or greater control. Sureguard (Flumioxazin) is a pre-emergent, post-emergent herbicide that is labeled for container and field grown nursery settings as well as landscapes.

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