The bane of woodlands!!! This nasty little invasive has the ability to takeover a woodland area with a “take no prisoners” approach. When we purchased our land in 2005, which included 3 acres of woods, there was a near monoculture of garlic mustard. We began in earnest to rid our woods of this even though “eradicate” and “garlic mustard” are never used in the same sentence.
Garlic mustard is a biennial herb. First year plants are a small rosette and second year plants grow much taller, flower, and set seeds, many, many, many seeds! These seeds are dispersed via foot traffic, animal fur, and water movement. Garlic mustard is allelopathic and can quickly outcompete any natives eventually leaving the woods with an unhealthy, singular flora component. My opinion is that it is never a good thing to have a monoculture. Diversity is the key to a good healthy environment. Frankly, that can be applied to all aspects of life!!!
The top picture shows a first year rosette. The bottom picture is a second year plant in flower.
Garlic mustard is one of the last plants to stay green in the fall and one of the first to green up in the spring. This is convenient from a killing perspective. Our regimen has been to spray with 2% glyphosate in the fall, generally around Thanksgiving, and then again in spring, generally around Easter. Then 2 weeks after the spring spraying, we go through and pull the ones that snuck by us. Over the 6 years of treating this way, the plant’s pervasiveness has decreased substantially, but in the process, I noticed garlic mustard plants coming up that were deformed, yet flowering and setting seed. I do not know if these seeds were viable, but I suspect the plants are becoming resistant to glyphosate. After talking with several other folks who regularly deal with garlic mustard, I decided to follow their advice and switched my herbicide to a low dose metsulfuron methyl. We sprayed this last fall, then did our burn rotation this spring, and now we’re hand pulling those that were missed. Although every year we’ve seen fewer and fewer, this year it’s remarkable how few there are and none are deformed.
To mention just a few of the plants that we enjoy in our woods now; these were suppressed prior to our war on garlic mustard. They include shooting star, Indian pipe, lady’s slipper, wild geranium, wood anemone, solomon’s seal, false Solomon seal, and yellow pimpernel. Below is a picture of our “purple carpet” of wild geranium. When these bloom, the woods have a wonderful light perfume-y aroma!