Garlic mustard (Alliaria petiolate) is a highly invasive plant species that poses a significant threat to the ecosystems of northern Wisconsin. The plant was originally introduced to North America in the 1800’s as a culinary and medical herb, this plant has since spread aggressively, outcompeting native vegetation and disrupting delicate ecological balances. Garlic mustard is a biennial herbaceous plant which means it completes its life cycle in two growing seasons. It thrives in shaded woodlands, disturbed areas, and along forest edges. In its first year, it forms a low-growing rosette of round leaves, while in its second year, it produces a flowering stem with small white flowers that can reach up to 3 ft tall, and remain in the soil for up to 5 years. The plant can also be easily identified by its heart shaped, toothed leaves and the garlic-like odor that is emitted when its leaves are crushed. Garlic mustard is particularly harmful due to it being able to release chemicals into the soil that inhibit the growth of native plants. Additionally, it forms dense monocultures, which shades out native seedlings and altering light and nutrient availability. Northern Wisconsin’s rich forests and diverse ecosystems make it particularly susceptible to garlic mustard infestations. Because of the region’s cool, moist conditions, it has been able to spread rapidly along trails, roadsides, and waterways. Human activity such as hiking and logging often facilitates its spread by transporting seeds on boots, equipment and vehicles. There are 3 different ways that are used to manage and control garlic mustard and the first is manual removal. Hand pulling is very effective, especially before the plant sets seed. Another way is using chemical control which can be used on large infestations, but there must be some care taken to avoid harming native plants. The last is early detection, monitoring and removing small patches early can prevent those large infestations of undesired plants. Some other ways the public can help is by learning to identify garlic mustard and report sightings of infestations to local conservation groups. Another thing that is good to do is clean your boots, clothing, and equipment after hiking or just being in the outdoors to avoid spreading seeds. All in all, garlic mustard is a formidable invader, but with awareness and collective action, its spread can be managed
Conservation Corner is a weekly article produced by the Forest County Land Conservation and Land Information Department. For more information contact Lucas O’Brien, Forest County Land Conservation Technician at 715-478-1387 or by e-mail at