My favorite method to control garlic mustard is with prescribed fire. Not only does it kill the weeds and their seed in the soil, it stimulates fire adapted native plant seeds to germinate. Not only will the fire control garlic mustard, but it suppresses the invasive shrubs that have degraded so much of our woodlands in Wisconsin.
Unfortunately, you must have a trained and well equipped which most private landowners find too difficult to find or expensive to afford. Garlic mustard also often grows in areas that lack enough ground fuel to carry fire through the weed patches.
While it may be too late to arrange a controlled burn this spring, now is a great time to begin planning for next year. The Wisconsin Prescribe Fire Council is a good place to start
Head to the Wisconsin DNR website for more information about controlling garlic mustard.