Garlic Mustard

Fact SheetTreatmentAlliaria petiolata

Invader Images

    • Garlic Mustard Leaves
      Garlic Mustard Leaves
    • Garlic Mustard Flowers
      Garlic Mustard Flowers
    • Garlic Mustard Infestation
      Garlic Mustard Infestation

Identification

Appearance

Alliaria petiolata is an herbaceous, biennial forb. First year plants are basal rosettes which bolt and flower in the second year. Plants can be easily recognized by a garlic odor that is present when any part of the plant is crushed.

Foliage

Foliage on first-year rosettes is green, heart-shaped, 1-6 in. (2.5-15.2 cm) long leaves. Foliage becomes more triangular and strongly toothed as the plant matures.

Flowers

Second-year plants produce a 1-4 ft. (0.3-1.2 m) tall flowering stalk. Each flower has four small, white petals in the early spring.

Fruit

Mature seeds are shiny black and produced in erect, slender green pods which turn pale brown when mature.

Biology

This is considered a watch list species

Origin

Garlic mustard was originally brought to the United States from Europe during colonial times as an early spring edible. It's tasty, garlicky flavored leaves make a fantastic pesto and great addition to soups. Help control garlic mustard by harvesting it in the spring and using it for culinary adventures.

Habitat

Abandoned Field, Agricultural Field, Edge, Open Disturbed Area, Pasture, Railroad Right-of-Way, Roadside, Utility Right-of-Way, Vacant Lot, Yard or Garden. Euphorbia cyparissias is most often found in old fields and natural grasslands.

Life cycle

Beginning in May (in the mid-Atlantic Coast Plain region), seeds are produced in erect, slender pods and become shiny black when mature. By late June, when most garlic mustard plants have died, they can be recognized only by the erect stalks of dry, pale brown seedpods that remain, and may hold viable seed, through the summer.

Ecological Threat

Alliaria petiolata is an aggressive invader of wooded areas throughout the eastern and middle United States. A high shade tolerance allows this plant to invade high quality, mature woodlands, where it can form dense stands. These stands not only shade out native understory flora but also produce allelopathic compounds that inhibit seed germination of other species. Alliaria petiolata is native to Europe and was first introduced during the 1800s for medicinal and culinary purposes.

Management Options

Mechanical Control

Hand removal of entire root system of plant is practical for light infestations. For larger infestations cut stems at ground level or within several inches of the ground, to prevent seed production.

Chemical Control

Herbicide (e.g., Roundup) may be applied for very heavy infestations. Fire can be used but can encourage germination of stored seeds and promote growth of emerging garlic mustard seedlings.

Biocontrol

Five weevils and one flea beetle feed on garlic mustard

**Be careful not to damage or kill nearby native plants when conducting management work. And when using herbicides, always follow the instructions on the label.**

Citations

Photo Credit

5476545, Chris Evans, University of Illinois, Bugwood.org

5510363, Caleb Slemmons, National Ecological Observatory Network, Bugwood.org

5492758, Steven Katovich, USDA Forest Service, Bugwood.org

Information Credit 

Go Botany

Bugwood

U.S. Forest Service