ISN hosted public workbees in Grand Traverse, Manistee, Benzie and Leelanau Counties. We would like to thank the 44 enthusiastic volunteers who put in over 132 hours of work pulling garlic mustard this month. With their help, ISN pulled more than 5,300 pounds from over 11 acres of high quality habitat. A big thanks to our partners, Oryana for providing a delicious garlic mustard lunch, our lunch host sites, and our volunteers for coming out rain or shine (or snow!) and making a huge dent in the populations of this invasive species at Magoon Creek, Tank Hill, Clay Cliffs, and the Nature Education Reserve at Oleson Bridge. Check out photos from our workbees!
Much of the garlic mustard we collect is shared with Paperworks Studios and turned into paper and greeting cards. Learn more about this exciting partnership as featured on 9&10 News and in the Record Eagle. Shop for garlic mustard greeting cards here!
We are gearing up for Japanese knotweed treatment! Japanese knotweed is a very tricky plant to control, and is a major threat to Michigan’s streams, wetlands, and other high quality habitats.
Key factsIntroduced: Introduced to the US in 1868 by settlers as a salad green and pot herb.
Key ID Features: Toothed, triangular to heart-shaped leaves. Rosettes of leaves or white flowers on tall plants.
Interesting tidbit: If harvested when young (before flowering), greens may be used in a garlicky salad green, or made into pesto! Garlic mustard has high levels of vitamins A and C.
What problems does garlic mustard cause?Like most invasive plants on the Top 20 list for the Grand Traverse region, garlic mustard replaces native plants in high quality natural areas, which in turn reduces critical food resources for birds, butterflies, and other wildlife. In addition to physically crowding out native plants-especially spring ephemerals like trillium and violets-garlic mustard releases chemicals into the soil that hinder the growth of other plants. Furthermore, few native herbivores will eat garlic mustard, giving it a large competitive advantage over native plants. The replacement of native plants by garlic mustard can hinder forest regeneration by limiting tree seedling growth. Garlic mustard seeds are able to live in the soil for at least 7 years before sprouting.
What does garlic mustard look like?
Garlic mustard is a biennial herb that usually grows to 2 to 3 feet when mature, though it spends its
Garlic mustard flowers and adult leaves. Photo by Wisconsin DNR.first growing season and the following winter as asmall leafy rosette. Leaves are triangular or heart-shaped, and are roughly and irregularly toothed. The second year stem is topped by clusters of small, white, 4-petaled flowers. All parts of the plant smell of garlic when crushed, especially early in the season. Adult plants die in midsummer, but persist as tall dead stalks with thin seed pods. Although tolerating a range of conditions, garlic mustard is most common in moist forest edges, open woods, and shaded roadsides.
How do I manage garlic mustard?
Pulling garlic mustard is very effective in small populations. Take care to remove the root, and pulling should be done inearly spring, before the plant goes to seed. Garlic mustard is an extremely hardy plant, and can re-sprout in a compost pile or if left out, and seeds can develop even if the plant was not flowering when pulled. There are many methods of disposing of pulled garlic mustard to explore. Larger populations may be managed through herbicide use; spraying is best done in early spring and late fall, when garlic mustard is one of the few green things, so there is little risk to native plants.
For more information on invasive plants:Visit HabitatMatters.org. You may also contact us to schedule an engaging presentation for your garden club or any group interested in improving landscapes for the benefit of natural areas.
Want to eat garlic mustard?Try one of these many resources for recipes, search for more, or make up your own!
Please make sure the area you harvest from has not been sprayed with herbicides.
Garlic mustard recipes from Friends of Silgo Creek
Garlic mustard and other recipes from Wildman Steve Brill
Eat it to Beat it! cookbook from Appalachian Forest Heritage Area
Roulade and ravioli from The 3 Foragers
From Pest to Pesto cookbook from Potomac Highlands CWPMA
Below, a few of the more common solutions for disposing of the invasive plant garlic mustard are discussed. Weigh the pros and cons of each option to find the one that best suits your needs!
Landfill - Small Populations
In 1994, legislation was passed to exclude compostable items from landfills, but exceptions were made for yard waste that is “diseased, infested, or composed of invasive species” (Michigan Natural Resources and Environmental Protection Act of 1994, §324.11521). This allows landowners to dispose of invasives they remove—such as garlic mustard—using the trash disposal system.
One option is for a city, village, township, or group to rent a dumpster from a disposal service for garlic mustard disposal. However, details concerning location, pickup schedule, monitoring for proper use, and funding should all be carefully considered during planning.
Individual disposal is also an option. In northwest Michigan, persons using Republic (or Allied before 2009), garlic mustard will be accepted if it is securely bagged. Bags do not need to be labeled with invasive plant stickers. Persons served by American Waste should double-bag and label the bags as invasive plants and drop them off at locations in Traverse City, Kalkasa, or Charlevoix. Customers will be required to pay for their extra bags in both cases.
Regardless of your trash service, please keep in mind that the fees for picking up bags differ depending on where you live. For the most accurate information, please call your trash collector:
Republic (231) 723-4940
American Waste (231) 378-4657
Waste Management (866) 797-9018
Location is key for tarping. The pile should be placed close to/on the site of the infestation to minimize spreading seeds in transport. Ideally, the pile would be in a non-sensitive area that is not readily visible from roads, trails, or other areas that people frequent, as it may be considered an eyesore. A few smaller tarped piles may be necessary to remain inconspicuous and within invaded areas.
Tarping requires annual monitoring for several years after the last plants are added. The tarp keeps plants from being moved and helps raise the temperature, but seeds will escape and sprout. The goal of tarping is to kill the plants and keep seeds in as concentrated an area as possible to make for easy future treatment.
One similar alternative to tarping is called “solarizing.” Instead of being piled, plants are placed in black, heavy-duty, contractor-strength garbage bags, tied off, then left in a place that gets plenty of hot summer sun for the year. The high temperatures achieved with the black plastic in the sun will kill garlic mustard seeds after 1 to 2 summers (depending on temperature); at this point the decomposing matter can be added to a compost pile. Monitoring areas where the bags sit and where regular composting is spread is still key.
Human Consumption - when possibleThe fact that all parts of garlic mustard are edible is the main reason it is in North America to begin with. Garlic mustard has a flavor similar to garlicky spinach and can be used as a salad green, sautee component, or even a pesto base. Many recipes can be found online; one is included below.
Generally speaking, garlic mustard is more tasty when it is young. It is mildest and has the most pleasing garlic flavor when it is growing new leaves just after it starts to bolt. More “bite” develops as the leaves age. Garlic mustard becomes bitter—unpalatable to some—once it flowers. This progression is advantageous for conservation of native habitats, as pulling garlic mustard is most effective early in the growing season.
Garlic Mustard Pesto (recipe from http://www.monchesfarm.com/PESTO.htm)
3 cups garlic mustard leaves, washed, patted dry, and packed in a measuring cup
2 large garlic cloves, peeled & chopped
1 cup walnuts
1 cup olive oil
1 cup grated Parmesan cheese
1/4 cup grated Romano cheese (or more Parmesan)
Salt & pepper to taste
Combine garlic mustard leaves, garlic and walnuts in food processor or blender and chop. With motor running, add olive oil slowly. Shut off motor; add cheeses, salt & pepper. Process briefly to combine. Serve warm over pasta or spread on crackers as an appetizer. It also makes a great topping for baked fish.
Others, like dairy cows, are not affected themselves, but there are reports of garlic mustard giving their milk an unpleasant flavor. Animals raised for their meat might experience a change in flavor, though if they are not fed garlic mustard for a few weeks before market it should not be a problem. Chicken eggs are not reported to be flavored by garlic mustard, and animals raised for fiber (sheep etc.) show no ill effects.
When transporting garlic mustard to animals, it is crucial to do so before the plants are flowering, to reduce the chance of spreading seeds. Garlic mustard has stores of energy that can allow it to flower and seed out even after being pulled. Additionally, great care must be taken to ensure that the garlic mustard fed to livestock is fresh. Never feed animals more than can be eaten in a day.
Composting - NOT recommended
There has been much interest in disposing of garlic mustard and other invasive species in ways that avoid landfills. Composting is an attractive option on the surface, as it creates a useable resource. However, composting garlic mustard is not as easy as it first appears and may actually cause this invader to spread.
Household compost piles and bins do not reach high enough temperatures to kill garlic mustard seeds. Jason Frenzel, of the Huron River Watershed Council and formerly with the City of Ann Arbor, was in charge of a review of composting invasives. He notes that compost temperature “is very contingent on many specifics: aeration, temp, moisture, time, mixing, etc. …It is really easy to not get complete composting. Backyard composting of invasives is a BAD idea.” If the seeds are not killed, garlic mustard will spread each time the compost is used. In fact, heat-hardy invasives like Japanese knotweed may never be truly destroyed by composting.
These problems of incomplete composting and seed dispersal persist for municipal compost piles. Even when appropriate aeration regimes are in place, most municipal composts are not carefully monitored for complete composting, leaving much room for error. Since the compost is often distributed and used throughout a large area, seeds lying dormant in the compost could then sprout in new places—evidence of this has already been seen in northwest Michigan. Ann Arbor, Michigan is one of a very few (carefully-maintained) composts found to be lethal to garlic mustard seeds.
In spring, garlic mustard often eclipses many of our other invasive species. For a change of pace, consider another Top 20 species, dame’s rocket (Hesperis matronalis). Dame’s rocket is a cousin of garlic mustard, with a similar life history (biennial–a little rosette for one year, then bolting tall and flowering in its second spring before it dies that summer) and bloom time. However, humans brought dame’s rocket for beauty instead of food. Luckily, dame’s rocket can be controlled in much the same way as garlic mustard–pulling is effective for small and medium populations and herbicide works best for very large ones. Dame’s rocket is especially a problem in natural areas that are near gardens, but the tiny seeds can spread far beyond urban parks. Learn more about dame’s rocket on our website.
ISN had some big goals!
When partners met this midsummer, garlic mustard, invasive phragmites, Japanese and giant knotweed, and Oriental bittersweet were identified as our highest-priority plants for the region. We then surveyed over 10,290 acres and 170 miles of shorelines–including shores of rivers, inland lakes, and Lake Michigan–to look for top-priority invasives. Though specifics varied by county, removing these plants from high quality natural areas and areas that would increase spread by the invaders (like roadsides) were made the main target for treatment.
Using grant money to protect high-quality habitats
Partners decided which areas that had been surveyed or had reported populations should be treated, many of which were public lands and State Game Areas. We applied for Aquatic Nuisance Control permits from the Michigan Department of Environmental Quality, gathered appropriate permissions, and coordinated treatments. This year, we were able to treat approximately 3,160 acres of high-priority invasive plants in the region to safeguard these crucial native habitats.
We’re also seeing some amazing native plant regrowth in areas that are now nearly phragmites-free! Many partners, like Portage Lake Watershed Forever, have seen similar results.
The Japanese knotweed project is newer and the plant is even harder to control than phragmites, often taking three or four years to control. With continuing to work with the DNR for best treatment options, we are hoping to see significant dents in treated knotweed populations come spring.
Garlic mustard is possibly the easiest to see great preliminary results with, though true control requires more time due to a long-lasting seed bank. This year, volunteers at the Tippy Dam pull in Manistee County reported that populations of this target plant were much lower than in previous years from pulling alone. Herbicide treatments this fall should help stem the tide of seedlings, making next spring’s work bees that much more effective! Similar results from pulling were seen at the Great Garlic Mustard Hunt in Grand Traverse County, and area where garlic mustard is still an early-stage invader.
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