Garlic Mustard

Miller, James H.; Manning, Steven T.; Enloe, Stephen F. 2010. A management guide for invasive plants in southern forests. Gen. Tech. Rep. SRS–131. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 120 p.

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is an upright cool-season biennial forb in small-to-extensive colonies under forest canopies, characterized by a faint-to-strong garlic odor from all parts of the plant when crushed (odor fades as fall approaches). It has basal rosettes of broadly arrow-point shaped leaves with wavy margins in the first year (remaining green during winter) and a 2- to 4-foot (60 to 120 cm) flower stalk and terminal clusters of flowers with four white petals in the second year. As a dead plant after June of the second year, it has long slender seed pods which ballistically disperse their seed up to 10 feet (3 m). Seed are spread by humans, animals, and water and can lie dormant for 2 to 6 years before germinating in spring. Stand density varies yearly depending on germination requirements of seeds in the soil seed bank, with a single crop germinating over a 2- to 4-year period.

Management strategies

Bag and dispose of plants and seed pods in a dumpster or burn.
Treat when new plants are young to prevent seed formation.
Pull, cut, and treat when seed pods are not present.
Repeat cutting and mowing to prevent seeding.
Minimize disturbance within miles of where this plant occurs, and anticipate wider occupation when plants are present before disturbance.
Manually pull when soil is moist to ensure removal of all roots.
Repeated annual prescribed burns in fall or early spring will control this plant, while “flaming” individual plants with propane torches has also shown preliminary success.
Clean shoes, equipment, and vehicles to prevent seed dispersal.

Recommended control procedures

To control two generations, thoroughly wet all leaves with a glyphosate herbicide as a 2-percent solution in water (8 ounces per 3-gallon mix) when plant is bolting (April through June) or Garlon 4 as a 1- to 2-percent solution (4 to 8 ounces per 3-gallon mix) in water (March through May). Apply glyphosate in winter anytime the ground is not frozen or snow present to provide control and safety to dormant native plants. Include a surfactant or an aquatic surfactant when plants are near surface waters. For more selective control, apply Plateau* (see label) where permitted.

* Nontarget plants may be killed or injured by root uptake.

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