Hey Mr. Green,
It is not fitting to speak poorly of one's neighbor, but to be very blunt, my neighbor Colonel Garlic Mustard is an invasive pest. I would like to know the most environmentally sensitive way to deal with him. It's so difficult for me to choose between the options that come to mind. Would you recommend a lead pipe or a wrench perhaps? I know you will appreciate how deeply concerned I am about minimizing my environmental footprint in this delicate matter. –-Dan, in Madison, Wisconsin
Invasive plants are more like colonialist exploiters than neighbors. One way to start to eradicate this invasive plant is to get out a weed whacker, or a scythe if you’re a low-tech or anti-tech kind of nature lover, and cut all the plants off at the ground when they’re beginning to flower. The operative word is “start to,” because garlic mustard is a biennial whose seeds remain viable for up to 5 years, according to authorities such as your Wisconsin Department of Natural Resources (which of course is threatened by the state’s now notorious governor, Scott Walker, which must please his anti-environmental political cronies and campaign donors like the Koch brothers).
You can also pull garlic mustard out by the roots when the plant is large enough, but this can be very labor intensive, and may disrupt the soil for other plants while encouraging new mustard plants to sprout by stirring up the soil. A third option is to fry them at the same stage of growth with one of those flame-throwing weed torches.
Since, like many other “weeds,” e.g., dandelions, garlic mustard is edible and nutritious, you might just try cooking it like you would other healthful greens such as kale, collards, turnip greens, and India mustard. The USDA’s nutrient data library www.nal.usda.gov/fnic/foodcomp/search doesn’t list the nutritional value of garlic mustard per se, but indicates that a cup of cooked India mustard can provide half recommended adult dietary allowance of vitamin C and over a third of vitamin A, while it also contains some micronutrients that may help protect against some types of cancer and other diseases. (If you would like to a few of my excellent recipes for greens, just contact me at the address above.)
You could of course kill the garlic mustard with Roundup if you zapped it early enough in the year, before innocent plants emerge that would perish as collateral damage in a Roundup raid (since it breaks down rather quickly, Roundup doesn't remain toxic to plants for very long). But I don’t recommend Roundup (or other brands containing its active ingredient glyphosate). Besides, if you douse that garlic mustard with poison you can't eat it, and in any case, you’d probably have to apply the Roundup for several years because its not going to kill the dormant seeds.
Invasive plants are a real threat to local ecosystems, so if extirpating the garlic mustard gives you a thrill, you could branch out into battles against other aggressive weeds, of which, alas, ther is no shortage. Your DNR publishes free online material about invasives, like its Field Guide to Terrestrial Invasive Plants in Wisconsin, available at http://dnr.wi.gov/invasives/ Many other states’ environmental agencies provide information on invasive (just search for the name of the state + “invasive plants”), and resources for all states are available from individual state or regional native plant societies, the Native Plant Conservation Campaign www.plantsocieties.org, and the National Network of Invasive Plant Centers at www.invasiveplantcenters.org.