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Extension > Extension in your Community > Douglas > County Horticulture Educator > Articles > Fall Is A Good Time to Spot Garlic Mustard

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Fall Is A Good Time to Spot Garlic Mustard

The fall weather has been fantastic, and many of us have spent these glory days enjoying the great outdoors.  While you are touring your garden, or taking a walk in the woods, keep your eyes open for garlic mustard. Garlic mustard is a restricted noxious weed, meaning it cannot be transported, sold or knowingly planted in Minnesota. Its seeds are usually not moved around by wind or birds, but are often transported through water or mud. These seeds can stay alive in the soil for a long time, causing issues every spring and fall. While it may seem like a hassle, removing soil from your boots before and after you leave a forest is a great way to avoid introducing invasive species, including garlic mustard. 

One challenging aspect of garlic mustard, aside from how it spreads, is how it effects other plants. Studies suggest garlic mustard is allelopathic, which means this plant sends out chemicals that hurt the growth of its neighbors. Garlic mustard releases glucosinolates, chemicals that harm a beneficial soil fungus called mycorrhizae. These fungi help provide important nutrients to plants in exchange for energy. Over time, a large garlic mustard patch can severely damage native plant populations that otherwise would thrive in the area.

How to identify garlic mustard

Because garlic mustard is a biennial weed, the first year of its life is spent as a rosette low in the forest floor. Often, it is confused with either wild ginger (Asarum species), creeping charlie (Glechoma hederacea), or violets (Viola species). One trick to find them is to scout in the late fall, as garlic mustard is one of the last green plants in the woods. Unlike creeping charlie and wild ginger, garlic mustard does not spread as a vine. Its first-year leaf edges are “scalloped," meaning they have blunt, shallow teeth on the sides.  It can also be identified by smell:

  • Crushing garlic mustard leaves can give off a mustardy, garlic odor. 
  • Violets will not have a strong smell. 
  • Creeping charlie will have a minty, herbal aroma. 
  • Wild ginger’s stems, if broken, will release a smell similar to ginger.

Controlling garlic mustard

If the area is small, hand removal of the plant and most of its root system could be an option.

For larger sites, herbicide applications are generally the favored technique. If you decide to go this route, a labeled herbicide that contains the active ingredient triclopyr (Garlon) or glyphosate (RoundUp) can be effective. 

Be aware that glyphosate products are non-selective, and will harm most actively growing plants if sprayed. Triclopyr normally does not hurt grasses and sedges, as it is more targeted toward broadleaves. (CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.)

So, enjoy the fall weather, and keep your eyes open for these weedy plants.  If they are on your property, use recommended measures to keep them from spreading! For more information about Garlic Mustard, visit: https://extension.umn.edu/identify-invasive-species/garlic-mustard