Garlic Mustard Season is Beginning: Tips and Tricks

Written by Dan Carter. Photos by Dan Carter.

April 6, 2026

Garlic mustard season is beginning. The image shows garlic mustard seedlings (left) next to a second-year plant (right) that will flower later this spring if we allow it. They are growing beneath walnut, boxelder, and common buckthorn.

Before you work to control it, I strongly encourage looking for underlying contributors to garlic mustard invasion. Garlic mustard is often most abundant where exotic brush or trees like walnut, black locust, white mulberry, or boxelder are present. These not only produce the shade garlic mustard likes, but their leaf litter decomposes rapidly. This rapid decomposition means that the litter fails to physically obstruct garlic mustard seedlings, and it also means that the litter releases nutrients and essentially fertilizes garlic mustard at the perfect time for garlic mustard to take advantage. I don’t bother doing anything about garlic mustard in those kinds of settings unless it is part of a restoration project that is also addressing  the underlying problem of high nutrient availability and excessive shade. Even then, I might not worry about a little garlic mustard if restoration activities cause the site to become dramatically sunnier and more exposed to drying winds, because garlic mustard competes poorly in such settings.

When I do control garlic mustard, I rely on the following:

1) Consecutive years of prescribed fire between fall and very early spring, if there is adequate leaf litter or other fuel. Garlic mustard is green through the dormant season, so burning at that time harms it. Very well-timed burns just after seedlings germinate (late March in southern Wisconsin) are very beneficial. Most second-year plants will survive fire, but have reduced vigor, but there will be few second-year plants if burns occur over a few consecutive years.

2) In late March or very early April I use a flame weeder (torch connected to a propane tank) when conditions are damp and there is no risk of starting a wildfire. It only takes a quick pass of the heat of the flame to melt away young seedling plants, and they won’t come back. Second year plants will be damaged, but most won’t be killed unless you keep the flame on them for long periods.

3) I pull second year plants beginning as soon as the ground thaws and continue through early flowering. Pulled plants do not need to be removed from the site so long as they aren’t left with good root contact to soil. Seed pods (siliques) that have not begun to fatten will not produce viable seeds.

I generally don’t foliar spray garlic mustard with herbicide, because I find the above approaches to be sufficient. Also, many desirable native species maintain green leaves through the winter, and if they are present, I don’t want them to get sprayed. They tend to be perennials that recover from flame weeding and benefit for dormant season fires.

(Regarding photos below) The first photo shows an area under a large white mulberry tree with many walnut trees coming up around it. These produce ideal habitat for garlic mustard and other weeds–fast-decomposing leaf litter that doesn’t smother plants that are green during the cold times of year and releases nutrients when garlic mustard can most take advantage. I wouldn’t bother with garlic mustard control in a setting like this unless it was a new arrival to an area or I was concurrently addressing the underlying problem, which here is white mulberry and walnut that don’t belong in a savanna. The second picture shows up close what is growing beneath the mulberry and walnut–abundant garlic mustard, dame’s rocket, and motherwort. The other carrot family thing probably is either sweet cicely or aniseroot (not sure). Those two species and other native woodland plants with sticktight seeds like white avens, honewort, and stickseed are often found in places like this. 

About The Prairie Enthusiasts 

The Prairie Enthusiasts is an accredited land trust that seeks to ensure the perpetuation and recovery of prairie, oak savanna, and other fire-dependent ecosystems of the Upper Midwest through protection, management, restoration, and education. In doing so, they strive to work openly and cooperatively with private landowners and other private and public conservation groups. Their management and stewardship centers on high-quality remnants, which contain nearly all the components of endangered prairie communities.