Garlic mustard disposal methods

​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

​Tarping/Solarizing - Large populations
​The principle of tarping is similar to composting.  Garlic mustard plants are pulled and collected in a single location.  When all pulling is complete, the pile of invasives is covered with a securely fastened heavy-duty tarp.  The pile is the left alone for the year, except for monitoring the pile for new sprouts.  Additional plants can be added at any time, including in later seasons and years, though the tarp must always be carefully replaced and refastened.

​Tarping garlic mustard in northwest Michigan. Photo courtesy Grand Traverse Regional Land Conservancy

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.

Livestock feed - when possible
​Garlic mustard is also possible to feed to livestock, allowing it to be used in a productive manner at a faster rate than humans can consume it.  If you have your own animals, consider adding garlic mustard to their early spring diet.  Garlic mustard is green before anything else, supplying the animals with vitamins very early in the season.  If you don’t own livestock, consider teaming up with a local farmer to bring their animals garlic mustard to eat.
​Some animals are better suited for garlic mustard consumption than others.  Animals with delicate digestion, like horses, should not be fed garlic mustard.  

Chickens eat garlic mustard at a northwest Michigan farm.

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.