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Hairy bittercress

Hairy bittercress
(Cardamine hirsuta)

Herbaceous annual or biennial in the mustard family, reaching up to one foot tall. Seeds eject from siliques (long slender seed pods) upon maturation.

Overview

Other names for this plant include:

  • Common names: bittercress, common bittercress, shotweed, pepperweed, snapweed

Ecological threat:

  • Invades grasslands, prairies, open and disturbed areas, and occasionally rocky cliffs and bluffs.
  • Readily self-seeds, creating large dense mats.
  • Seeds are easily spread by human activity.
  • Commonly occurring container-weed from the nursery industry

Classification in Wisconsin: Not Regulated

The recommendation for Bittercress was based upon this literature review developed by the department.

Identification

Leaves & stems: Leaves are alternately arranged on the central stem. Stems are glabrous. Leaves occur from basal leaf petioles which have fine hairs at the base and have two-four pairs of leaflets. Basal leaflets are the same in length as in width.

Flowers: Small white flowers (2-3mm), with four petals and four stamens, occur in racemes (clusters) at the ends of the flowering stems.

Fruits & seeds: Seeds are born in slender siliques (seed pods) that are ejected as far as ten feet upon maturation.

Roots: Taproot with shallow fibrous rootlets.

Similar species: Hairy bittercress closely resembles numerous other species in the mustard family including Small-flowered bittercress (Cardamine parviflora arenicola; native), Pennsylvania bittercress (Cardamine pensylvanica; native), and Wavy bittercress (Cardamine flexuosa; non-native). One distinguishing feature of this invasive species is its hairy petioles (particularly the basal) and hairs at the base of its flowering stalk, becoming hairless further up the stalk. Basal leaflets are as long in length as across in width.

Distribution

Cardamine_hirsuta
Counties in WI where Hairy bittercress has been reported (as of April 2013). Both vouchered and unvouchered reports included.

Do you have Hairy bittercress in your county but it isn't shaded on the map? Send us a report.

Control

Mechanical:

  • Digging out plants is the most effective method of control. Be sure to remove plants before seedheads develop.
  • Plants in flower or seed should be bagged and disposed.
  • Clean all equipment and boots from infested areas to reduce spreading seeds.

Chemical:

  • Bittercress is resistant to many types of herbicide. Spraying with glyphosate gives some longer lasting control.

Photos

View Bittercress pictures in our photo gallery!

Resources

Sources for content:

  • USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory
  • Virginia Tech Weed Identification Guide

Links for More Information

Last revised: Wednesday April 29 2015