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Garlic mustard

Quick facts

  • Garlic mustard is a noxious weed that spreads primarily by seed.
  • Garlic mustard grows in mounds and has clusters of small white flowers and scalloped green leaves that smell like garlic when crushed.
  • You can remove small sections of garlic mustard in lawns and gardens by hand digging.
  • Large infestations may require chemical control in early spring or late fall to avoid harming non-targeted species.

The Minnesota Department of Agriculture designates garlic mustard as a restricted noxious weed, and the Minnesota Department of Natural Resources defines it as an invasive terrestrial species.

In naturalized areas, garlic mustard should be reported using the Great Lakes Early Detection Network App or EDDMapS Midwest, and like other noxious weeds, should be controlled on-site if possible to minimize spread.

Characteristics

A patch of garlic mustard

Garlic mustard (Alliaria petiolata) is a member of the Brassica family and is also known by common names such as jack-by-the-hedge and garlicwort.

This noxious weed is an herbaceous biennial (a plant that completes its life cycle in two growing seasons). Typically growing between 2 to 4 feet tall, garlic mustard outcompetes native plant species in woodland regions. When torn or crushed, garlic mustard parts emit a strong garlicky scent.

Flowers, fruit and seeds

Garlic mustard flower and mature leaves
  • Bloom time: spring to early summer.
  • Like all members of the Brassica family, garlic mustard has clusters of small, four-petaled white flowers.
    • Flowers grow primarily at stem tips and leaf intersections (axils).
  • After flowering, garlic mustard produces 1- to 3-inch slender green capsules (siliques) containing between 100 to 10,000 tiny black seeds.
  • Garlic mustard siliques disperse their seeds in late spring, summer, and early fall. 

Leaves

First-year garlic mustard can be mistaken for many other plants.
  • Bright green with a coarsely toothed or scalloped edge.
  • During the first year of growth, plants form basal rosettes with scalloped, kidney-shaped leaves.
  • During second-year growth, leaves form into heart or triangular shapes with more rigid edges.
  • Alternate growth.

Stem and roots

  • Garlic mustard typically has a singular weak main stem.
  • Garlic mustard has a taproot that curves, forming an S shape, directly under the soil to provide stability to the plant.
Garlic mustard roots

Where it thrives 

Garlic mustard thrives in disturbed soils and can indicate chemical disturbances or natural disturbances such as flooding or erosion. This weed is a common opportunistic plant and is quick to occupy spaces where vegetation has been removed.

Garlic mustard is most often found in the understories of trees in moist, shaded environments; however, it can grow in most environments due to its high adaptability.

Garlic mustard is suspected to have allelopathic qualities, making it a competitor of desirable plants. 

Control and management

Garlic mustard requires committed removal to control its spread. Removal should be done in the spring, before flowering and seed pod formation. Seed capsules release 100 to 10,000 seeds per year. Garlic mustard can continue to set seed after being pulled, so it should be removed before flowering.

Pulled garlic mustard plants with flowers should be burned or bagged and allowed to decompose to minimize seed spread. Disposal of garlic mustard in landfills is illegal and transportation is only allowed to disposal sites and requires proper protection to prevent seed dispersal.

Check with the Minnesota Department of Agriculture (MDA) and Department of Natural Resources (DNR) for further information on safe and legal control.

Turf 

  • Hand removal is effective for removing small patches but may need to be repeated.
    • Remove all parts of the roots and shoots to prevent regrowth.
  • A dense and healthy turf is the best defense against garlic mustard encroachment.
  • Selective chemical control is most effective when applied in early spring or late fall with minimal damage to grass and sedges.
  • Chemical options with minimal damage to grass and sedges include:
    • Triclopyr alone
    • 2,4-D amine alone
    • 2,4-D + dicamba
  • Glyphosate is a non-selective herbicide and should be applied in early spring and late fall when other plants are dormant.

Garden

  • Garlic mustard can be prevented by cleaning tools and clothes before use.
  • Hand removal is effective for removing small patches but may need to be repeated.
    • Remove all parts of the roots and shoots to prevent regrowth.
  • Fill spaces where garlic mustard is removed as soon as possible with appropriate plant species. Find more ideas for plant selection.
  • Broadleaf herbicides are effective on large patches but should be used cautiously to avoid damaging desired garden plants.

Benefits to the landscape

Planting or propagating garlic mustard in Minnesota landscapes is illegal.

Existing plants are edible and are noted by foragers such as the Forager Chef and Four Season Foraging.

Conservation, invasive status, and native status

  • Restricted Noxious Weed.
  • Invasive.
  • Introduced.
  • Garlic mustard originates from Europe, Africa, and Asia. The introduction of the plant to the United States as a medicinal and edible plant can be traced back to the 1800s.

Plants that look similar

Management strategies for natural areas and large plant populations

Preventing the introduction and spread of garlic mustard to new locations is the most effective form of management. Seed is spread primarily by gravity, but it can be carried to new locations by people and wildlife, such as in seed mixes or soil attached to boots. Thoroughly cleaning shoes, clothing and equipment after hiking is good practice, as is buying seed from reputable sources. 

For more information about prevention visit PlayCleanGo. Most importantly, make sure you spread the word about prevention to others.

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Authors: Angela Gupta, Amy Rager, Megan M. Weber, Extension educators; Noah Burley, horticulture graduate student, College of Continuing and Professional Studies

Reviewers: Julie Weisenhorn, Extension horticulture educator, and Jon Trappe, Extension horticulture, turf and urban greenspace educator

Reviewed in 2024

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