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GREATjU RIVERlRIPW GREENING Forbs Garlic Mustard (Alliaria petiolata) Description Garlic mustard is native to Europe. In Minnesota, it is listed as a restricted noxious weed. Garlic mustard invades woodlands, riparian forests, and disturbed ground along forested roadsides, trails and waterways. Its proliferation in Minnesota native ecosystems has had a significant impact on forest understory habitats. It is able to spread aggressively, create large monocultures, outcompete native forest ground layer species, and displace ecologically important components of the native flora. Habitat suitability for native wildlife is severely reduced where garlic mustard has taken hold. Garlic mustard is an early season biennial herb with coarsely toothed, alternate, triangular to heart - shaped leaves that release a garlic -like smell when crushed. Evergreen basal rosettes are produced from seeds the first year. In the second year, the rosettes mature and bolt, producing erect, 1- to 3-foot tall stalks. Small 4-petaled white flowers develop into slender 1-2.5 inch long seed capsules, each with a single row of oblong black seeds. Garlic mustard reproduces via the prolific seed it generates. A single garlic mustard plant drops hundreds of seeds that remain viable in the seed bank for up to five years. The seeds are readily dispersed initially from the tall stiff flowering stems that catapult the seed away from the mother plant and secondarily via soil displacement during erosion events and when soil containing the seed is picked up on the feet of wildlife or humans or on tools and equipment. Eradication of garlic mustard may not be feasible. However, there are areas that are a higher priority for control. Strategies for control include maintaining zero tolerance for seed production in priority areas. Volunteers can be utilized to monitor and prevent establishment of new isolated populations. Mechanical If a population of garlic mustard is small enough, the best option for control is to manually pull the plants before they develop seed and bag them for removal. If the infestation is too large or too dense for hand removal, Weed whipping or mowing are viable control options. It is essential to mow before the plant flowers because garlic mustard will continue to develop seeds even after being cut. It is recommended to mow vegetative plants to the ground with a flail mower to shred the plant and prevent seed production. If the plant is in flower or past flower, mowing will spread the seed and increase the infestation footprint. Careful attention to sensitive native plants around the mowed areas will need to be taken to ensure they are not impacted. Mowed garlic mustard will either die or may form new flowers; however the plant will be much shorter and will typically produce fewer seeds. A second mowing is sometimes needed to treat the regrowth. In fire dependent ecosystems, prescribed fire is an effective management tool against first year garlic mustard, if there is sufficient fuel to carry a fire. Second year garlic mustard will potentially sprout following a burn, so follow up treatment is required. Prescribed fire is best used as part of an integrated management approach in which mechanical or chemical control are used as a follow-up treatments. Spot treating small populations with a propane torch can be effective on garlic mustard seedlings. Where garlic mustard is found growing amongst native wildflowers, it should be hand pulled. Garlic mustard pulled when it is flowering or in seed should be bagged in black plastic bags and allowed to "cook" to kill the seed. Chemical Garlic mustard can be chemically treated with glyphosate in early spring before flowering or in the late fall when native plants are dormant. Glyphosate is a nonselective herbicide and will kill all plants