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Invasive Species Sheet - Narrow-leaf Bittercress

Narrow-leaf Bittercress (Cardamine impatiens L.)

  • Alternate Common Name: Bushy Rock-cress
  • biennial herbaceous plant; with erect form; 6"-31" tall; shiny green in color
  • stem leaves alternate; numerous (6-20); thin and pliable; up to 4" long, or longer
  • lower and middle stem leaves have 6-9 pairs of long-pointed, somewhat lobed leaflets
  • small ears of the leaf bases remain on the mainstem when the principal leaves are removed
  • flower petals may be absent; if present, 4, white, tiny (1/10" long or less); in June
  • fruit is a slender, upward-growing, string bean-like silique 6/10" to 3/4" long;

Narrow-leaf Bittercress is similar to the native Pennsylvania Bitter-cress (Cardamine pensylvanica Muhl.) in that it has lobed or toothed leaflets on a tall, erect mainstem; tiny, white flowers; and the basal leaves may be few or absent by the time it flowers. Narrow-leaf Bittercress is differentiated by the downward-pointing "ears" at the base of the leafstalks. When a leaf is removed, the ears remain on the mainstalk. As is typical of other species of Bittercress, the fruits open from the base with two deciduous strips coiling up to reveal the seeds attached to a central membrane. The young seedling leaves do not resemble mature leaves (see photo of seedlings in pot). The
first year, the plant lacks the tall, flowering stalks.

Narrow-leaf Bittercress grows vigorously in disturbed areas, covering the ground in dense (but easy-to-pull up) patches. The plant is currently uncommon, but increasing, in New England.