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Weed Identification

Fernald's yellowcress



Scientific Name

Rorippa palustris spp. fernaldiana

Other Common Names:

bog marshcress
common yellowcress
marsh yellowcress
yellow watercress
bog yellowcress

Synonyms (former Scientific Names):

Rorippa islandica
Rorippa hispida


Seedlings have 1-2 cm long, stalked, egg-shaped cotyledons. Mature plants have slender pale yellow taproots that give rise to a basal rosette of deeply lobed leaves. Several 30-80 cm upright flowering stems grow from the rosette.


Leaves have 3-7 large lobes with toothed margins, stalks sometimes have lobes attached.

Identifying Characteristics

No rhizomes, shallowly toothed leaves, yellow flowers.

Flower Seed Head

Clusters of yellow flowers on the ends of branches and in the up most leaf axils appear June through September. Flowers have 4 petals 1 to 2.5 mm long.

Seed Fruit

Cylindrical fruits with 2 chambers each containing several seeds curve upward to a point. Seeds are 0.6 mm long, yellow brown, and egg-shaped.

Where Found

Found all over the United States. Marsh yellowcress prefers the wet, heavy, nutrient rich soils of poorly drained ditch banks, pastures, meadows. It is now being found in nursery and small vegetable crops.

Life Cycle


Plant Type