This post was written by Amanda Davis, a biology student at West Virginia Wesleyan College.
Last year, I went on a “Garlic Mustard Pull” at Seneca Rocks with the Appalachian Experience team at Wesleyan. We pulled this invasive plant species because it is causing a decline in native understory species and the organisms that depend on them. One year later I was surprised to find that garlic mustard has had positive applications throughout history. Because of its medicinal properties and its spicy flavor, garlic mustard is truly a jack-of-all-trades and a master of all!
Look out! We’re being invaded!
Garlic mustard is a biennial flowering plant in the mustard family, Brassicaceae. This family also contains broccoli, kale, cabbage, and cauliflower. Garlic mustard was introduced to the United States from Europe. Since then, it has greatly impacted native ecosystems. One example is demonstrated by its effect on the mustard white and West Virginia white butterflies. These butterflies normally lay their eggs on toothwort, a common spring ephemeral in the eastern United States. In many areas, garlic mustard is outcompeting toothwort populations. If toothwort is unavailable, these butterflies lay their eggs on garlic mustard instead. When larvae emerge, they are unable to complete development and die due to garlic mustard’s toxicity, thus decreasing the number of butterflies that reach adulthood.
What explains garlic mustard’s success as an invasive?
Since garlic mustard’s introduction to Long Island, New York in 1868, it spread across the United States reaching Oregon by 1959. Why did it spread so effectively?
Like other members of the mustard family, garlic mustard has cyanide in its leaves, which kills off essential soil bacteria and reduces the ability of fungal spores to germinate. As a result, native plants cannot absorb water and phosphorus as easily, causing garlic mustard to spread rapidly across an area. Luckily, garlic mustard is not harmful to us. Another reason garlic mustard has had invaded so effectively is that it has adapted to increase its chances of seed dispersal and germination by producing 8,000 seeds per plant! With such high seed numbers, the ability to self-fertilize, and no natural predators in the United States, it’s no wonder garlic mustard dominates most plants in its path.
Insects to the rescue!
In response to the invasion of garlic mustard throughout the United States, the University of Minnesota has proposed a biological control – the release of Ceutorhynchus scrobicollis, a weevil beetle from Europe. If approved the beetle will be released to prey on garlic mustard in 2016.
In its native habitat of Northeastern Europe, garlic mustard is not a pest and has been used as medication to treat gangrene and ulcers. Interestingly, researchers have found evidence of garlic mustard seeds in cooked animal and fish on ancient pottery shards in what is now Denmark and Germany. Even prehistoric Europeans liked a little zing to flavor their food!
A bad rap leads to a bright future
Following the “if you can’t beat them, eat them” philosophy, people from the United States have recently been whipping up impressive recipes that integrate garlic mustard or pesky weeds. It seems we are finally making the best of a bad situation. People are even organizing garlic mustard cook offs! I plan to try this garlic mustard pesto: http://sustainablepossibilities.blogspot.com/2014/05/weeds-if-you-cant-beat-them-eat-them.html.
Due to the introduction of beetles and use of garlic mustard by people in the United States, the invasion of garlic mustard may one day no longer be an issue. In the mean time, fire up the grill, throw on some steaks, and toss in a little garlic mustard seed. Don’t plant it in your garden, though, or garlic mustard might be the only plant you’re eating!