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Garlic Mustard

 

Garlic mustard

Garlic mustard can be readily identified by its distinctive scent and leaf shape
Photo © Jodie Shimp

Combatting the Threat of Invasive Species

The Conservancy's work to address the impacts of invasive species is coordinated by the Invasive Species Initiative.

Garlic mustard

Volunteers clear garlic mustard from woodland habitat. Photo © Connie Gray 


Brought to North America by 19th-century European immigrants, garlic mustard has become an invasive weed in many states east of the Rocky Mountains. Its garlic scent makes it easy to identify in most seasons of the year. It is this quality which led to its introduction as an herb here in the United States.

Garlic mustard is shade tolerant and can thrive in woodlands without any natural control. It crowds out native plants and flowers and becomes the main ground cover. Even a small area of the plants can produce thousands of seeds, which survive dormant in the soil for as long as five years.

In residential areas or where garlic mustard hasn’t taken over large plots, pulling and spraying in the spring are traditional control measures. Because pulled plants can still produce mature seeds, they must be bagged and removed from the site to prevent reseeding. Spraying individual plants with herbicide is just as labor intensive. Each year at Trice Dedman Woods in Missouri, the Conservancy sprays and pulls garlic mustard on more than 70 acres.

Oak woods like Trice Dedman, however, fare better with spring burning. The fire destroys the seeds in the leaf litter and burns the root crown of existing plants, breaking the cycle of invasion. Since 1989, the Conservancy and the Missouri Department of Natural Resources have burned a 10-acre test plot at Trice Dedman Woods and found that the garlic mustard has not come back. The test plot gives hope that the Conservancy will be able to control this invasive on a larger-scale in the future and make room for the native plants that help make up a vibrant woodland community.