Plant Profile: Rorippa palustris L.

Marsh yellowcress and southern yellowcress (Rorippa teres), belonging to the Brassicaceae family, are closely related winter annual weeds found extensively across the United States. These plants thrive primarily in damp environments but are adaptable to various conditions. They typically develop a rosette of deeply lobed leaves and produce upright, branched flower stalks. As they mature, the leaves exhibit even deeper lobing. In container settings, marsh yellowcress usually grows a single upright stem that branches only at the flowering stage, while both species can create well-branched mounds. The flowers are yellow, and they give rise to cylindrical fruit that contains numerous small tan seeds. The two species can be distinguished by their fruit pods (siliques): marsh yellowcress has seed pods on short stalks (approximately 1/2 inch), whereas southern yellowcress either has no stalks or very short ones. Both species germinate in the fall or spring in cool, moist soil and can be effectively managed with several preemergence herbicides, although the rankings of herbicide effectiveness are derived from limited experimental data.

Additionally, this plant is referred to by its Latin name, R. islandica.