Garlic Mustard Alliaria petiolata

Basic info - Garlic mustard is a flowering plant in the mustard family, first introduced to the US from Europe for medicinal and culinary uses, as well as for erosion control, in the 1800's. 

Impacts - This herb spreads quickly through rhizomes and wind-blown seeds, taking only a few years to infest an area, forming large colonies which crowd out native plant species and destroy food sources and habitat for wildlife. Garlic mustard not only shades out native plant species, but also releases compounds into the soil which inhibit seed germination of other plant species. It also emerges earlier in spring than many native plants, giving it an advantage. 

Identification - Garlic mustard can be 1 to 4 feet tall [3,5], and blooms in May-June with clusters of small, white flowers. Each individual flower has four petals and is only about 1/3 inch across [3]. This herb is biennial, which means it takes two years to complete its life cycle, and has differing growth forms depending on which year you find it in. In its first year, the plant is much smaller with only a few, round or kidney-shaped leaves with scalloped edges. Second-year plants have larger, triangular or heart-shaped leaves that are up to 3 inches long and wide, and are coarsely toothed along the edges [3]. Its seeds are black and shiny, produced in thin green to pale brown pods.

The easiest way to identify Garlic mustard, though, is by crushing any above-ground part of the plant, as it gives off a garlicky scent. Below ground, the roots tend to smell like horse radish. 

What can you do to help? - If you've identified Garlic mustard, or think you might have but aren't sure, you can report your discovery on the EDDMapS (Early Detection and Distribution Mapping System) app or website, or upload an image of it to the iNaturalist app.

These plants can be pulled by their roots, but be sure to do so before it sets seed, as the pulling action can cause the seeds to spread. Its foliage can be sprayed with herbicide. Once removed, you can dispose of the plants in plastic bags or by burning them. Never compost invasive plants!

Alternatively, since all parts of this plant are edible, you could use the young leaves in salads and sauces, use the roots in soups and stews, and use the seeds as seasonings. Use caution, as older plants can contain some cyanide, so if not using young plants be sure to cook thoroughly! Be sure to harvest the whole plant if using for food so as to prevent its spread. 

You can also plant a number of native alternatives to the invasive Garlic mustard, such as Canadian wild ginger (Asarum canadense), wild strawberries (Fragaria virginiana), or Canada Mayflower (Maianthemum canadense). 

Learn more - UIUC Invasives