Garlic mustard

Identification

Look for the combination of characters below. A single feature is rarely enough, especially when a native look-alike is present.

First-year rosette

A ground-level rosette usually less than 8 inches tall. Leaves are kidney-shaped with rounded teeth, usually less than 4 inches across, and smell of garlic when crushed.

Second-year stem

The flowering stem can range from a few inches to 3 feet tall. Stem leaves are heart-shaped, 2 to 4 inches across, with pointed, irregular teeth.

Flowers

Clusters of white, four-petaled flowers appear at the growing tip, beginning in early spring and continuing through early summer. Flowering is often staggered within a population.

Seed pods

Flowers are replaced by branched stems of slender green siliques that turn brown and brittle when ripe. Each tiny brown seed is less than a quarter inch long.

Odour

Crushed leaves and stems have a distinct garlic smell. This separates garlic mustard from several native plants with similar white flowers or leaf shapes.

Look-alikes

• Cut-leaf toothwort

  Cardamine concatenata

  Cut-leaf toothwort has compound leaves and white four-petaled flowers. Garlic mustard has simple kidney- or heart-shaped leaves and a garlic odor when crushed.

• Sweet cicely

  Osmorhiza claytonii

  Sweet cicely blooms at about the same time and can be confused at a glance. Check the leaf shape and crush a leaf. Garlic mustard smells strongly of garlic.

• Creeping charlie

  Glechoma hederacea

  Creeping charlie leaves can resemble first-year garlic mustard, but creeping charlie does not have a garlic odor when crushed and grows as a trailing perennial.

Range and status

Native range: Europe

Regulatory status by state

• Pennsylvania Noxious weed

  Garlic mustard is a Class B noxious weed on the Pennsylvania Department of Agriculture list. Noxious weeds cannot be sold, transported, planted or otherwise propagated in the state. Class B means the plant is widely established and cannot feasibly be eradicated.

  Pennsylvania state profile Regulatory source

• New York Prohibited

  Garlic mustard is prohibited under 6 NYCRR Part 575. Prohibited plants cannot be sold, imported, purchased, transported, introduced or propagated in New York.

  New York state profile Regulatory source

• virginia Noxious weed

  Garlic mustard is a Tier 3 noxious weed in Virginia under 2VAC5-317-20. Moving a listed noxious weed requires a valid certificate or permit.

  Regulatory source

• Ohio Prohibited

  Garlic mustard is on Ohio's invasive plant list under OAC 901:5-30-01, which bans selling, propagating, distributing, importing or intentionally spreading it.

  Ohio state profile Regulatory source

• Wisconsin Restricted

  Wisconsin classifies garlic mustard as Restricted under NR 40. Restricted species cannot be transported, transferred or introduced without a permit; possession is allowed except for fish and crayfish, and control is encouraged but not required.

  Wisconsin state profile Regulatory source

Why it matters

Garlic mustard spreads from forest edges into mature forest understories and can form dense monocultures that leave little room for native plants. It produces many seeds and releases antifungal chemicals into the soil that can disrupt associations between native plants and mycorrhizal fungi. Its seedbank persists for years, so control requires a multi-year plan.

Management