Cardamine hirsuta hairy bitter-cress Brassicaceae CAHI*; Bx, pb (DeCandido 2001), sv (Torrey 2017); NY, hb; R (DeCandido 2001);


Cardamine hirsuta.Leo (Accessed 5/2014).

Cardamine hirsuta.Leo (Accessed 5/2014).

Cardamine hirsuta is an annual, winter annual herb, stem 10-40 cm tall, smooth. Name hirsuta is rather misleading since this plant looks hairless without a lens. Even then, hairs are sparse. 

Leaves alternate, mostly in a dense basal rosette, pinnate, leaflets rounded, short-stalked, terminal leaflet larger, often lobed, stem leaves few, inconspicuous, becoming narrower towards top of stem, leaf stalks hairy, at least at base (use lens). 

Cardamine hirsuta flower. Carl Farmer.

Cardamine hirsuta flower. Carl Farmer. (Accessed 12/2014).

Flowers white, 4-parted, petals 0.2-0.3 cm long, sepals green, shorter; inflorescence crowded at top of a gradually elongating stem with a few small pinnate leaves; blooming March-April. 

Fruit green, often purplish, eventually becoming dry, capsules linear, to 2.5 cm long, developing below flowers on the elongating stem. the uppermost fruit often longer than the inflorescence; . 

Cardamine hirsuta.Walter

Cardamine hirsuta developing fruit. Walter (Accessed 12/2014).

Wetland status: FACU. 

Frequency in NYC: Very infrequent. 

Origin: Europe. 

Habitat: Lawns, gardens, weedy areas, open moist soil. 

Notes: Very common agricultural, nursery, and garden weed outside NYC, often forming mats of seedlings and small plants (Altland 2006).