Garlic Mustard…Thug of the Woods

This time of year, I go for walks in the woods. I notice native spring ephemeral wildflowers such as spring beauty, trout lily, bloodroot, and many others. However, I have a hard time ignoring one particular plant that seems to thrive in every woodland…the invasive exotic garlic mustard, Alliaria petiolata. This plant, native to large parts of Europe, Asia, and northern Africa, was brought to North America as a source of food, medicine, and erosion control. However, it has spread widely into natural areas in the northeastern United States since the 1860’s.

Shown on the left, garlic mustard gets established in disturbed sites as well as undisturbed woodlands rather easily. Here’s the problem…it is known to disrupt our local ecosystems in several ways. First, like other invasive plants, it takes up space, light and other resources that would otherwise be used by native wildflowers, grasses, and seedlings of woody plants. Worse, and even more disturbing is that garlic mustard has been found to exude phytochemicals into the soil which disrupt the relationship between the roots of native plants and beneficial soil fungi called mycorrhizae, which helps plants absorb water and nutrients. Basically, it causes other plants to not grow so well, while creating conditions that lets its own species grow really well!

Garlic mustard is pretty easy to identify at this time of year (mid-April) when it flowers. First, the flowers have four petals, like all the other plants in the mustard family. Second, the leaves are heart-shaped, and have toothed or wavy edges. Third, if you crush the leaves, they smell pungent and garlicy. If you still are not sure of the identification, download and use the iNaturalist app on your phone and go through the process of identification. You are also welcome to email a photo to Joe and I will help you identify your plant.

The bottom line is that garlic mustard impacts the growth of our native forest trees, shrubs, and other plants in a few different ways. What can we do??

Activity for All Ages: Go pull garlic mustard! Once you have learned how to identify it, it is pretty easy to pull up. Start on your own property. If you own some woodlands, or your property borders the edge of woods, look for this plant and try to pull it up by the roots. The photo on the left shows a recently pulled plant, roots and all. If you don’t get the roots, it will re-sprout. On the property where I used to live, I pulled garlic mustard each spring on about 1/3 of an acre of woods. I would actually throw it away in the trash so that there was no chance it would continue producing seed. You will notice that the later in the season we go, garlic mustard you have pulled still continues to try and flower and make seeds. It is like a “zombie plant”… if you leave it on the ground after pulling it, especially in the latter part of April or into May, it might keep growing!

Another Activity for All Ages: EAT IT. Since it was likely brought to North America on purpose for food and other uses, why not give it a try! Here is a good website for recipes and more information about harvesting garlic mustard. This might be a good activity to do with the kids as long as you monitor them. Just be careful about picking garlic mustard in places that might have been sprayed with herbicide or if there is poison ivy or other plants growing among them. Just be careful what you pick and process to eat. Write back and let us know if you tried any and in what recipe.

Garlic mustard is a biennial, which means that it is a plant that lives two years. In the first year, it sprouts and forms a small “rosette” of leaves on the ground. The photo on the right shows a new crop of seedlings that have sprouted this April. They will flower next year, and after they flower and produce seeds, will die. Take a look on your property for these little seedlings. They look like a few other plants, including a mint called ground-ivy. To be sure it is garlic mustard, crush some and smell it to see if it smells like garlic.

If you are interested in turning your property into an oasis of native plants, butterflies, wildlife, and birds, consider taking the Delaware Nature Society on-line class “Becoming Nature’s Best Hope“, which teaches about how to take Dr. Doug Tallamy’s ideas in his book “Nature’s Best Hope” so that you can put them into practice on your property.

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