Garlic Mustard -- a Foe to Dread

Garlic Mustard, a seemingly harmless biennial herb, has been invading the U.S. for over 100 years. In the 1800’s European immigrants brought it here to use in cooking and it was thought to have some value as a medicine. Since its first appearance on the eastern shores it has traveled across the United States infesting native areas to the point where native plants are choked out of the region. Quietly, these and other exotic invasive plants are taking over the ecosystems around the United States. Garlic mustard is proving to be one of the most damaging. Along the banks of many rivers, including the Wisconsin River it is crowding out native plants. When these plants disappear, native butterflies no longer have a host plant for their eggs and they disappear too.

Garlic Mustard First Year Plant What does this intruder look like? A first year plant generally has a cluster of 3 or 4 round scallop edged leaves rising 2-4 inches in a rosette. First year plants will remain green all winter.

Garlic Mustard Second Year Plant Second year plants range from 12-48 inches producing one or two flowering stems with numerous white flowers that have four separate petals. Leaves are heart shaped to triangular. Garlic mustard is the only plant of this height in our woods with white flowers in May. It has been known to displace native species within ten years. It is a threat to the survival of our native woodlands.

Infestations may be thwarted by hand pulling plants including the roots at or before the start of flowering. The flower stalk could also be cut as close (one inch preferable) to the soil as possible just as flowering begins. Cutting before this time may promote resprouting. Once a plant has flowered it can produce hundreds of seeds for each plant.

Seeds can lie dormant for 20 months before germination in addition they may be viable for five years! Animals, including dogs, flowing water and human activity, may distribute the seeds. For small areas or where there are large groups of people involved, hand pulling garlic mustard can be effective. All plants must be bagged and labeled “Invasive Species-approved by DNR for landfill”. Plants can’t be composted.

Information provided by the WI Department of Natural Resources