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  • Murray Moore

Guerrilla no more: Ex-plant puller tells all

Updated: Jan 21, 2023

By Murray Moore

I used to be a guerrilla invasive plant puller. For five, six, springs, I removed, from a nearby woods, Alliaria petiolata, better known as garlic mustard.

This European herb is spreading into the woods, threatening the woods’ healthy population of trillium, bloodroot, blue cohosh, mayapple, trout lily, and more native plants. Garlic mustard is bad not because it is a non-native plant, but because it replaces other plants and threatens the biodiversity of many native ecosystems.

Tuesday, June 2, 2020

Europeans brought garlic mustard to North America in the late 1800s since – the plant’s name is the clue – the crushed leaves smell like garlic. With no natural enemies on this continent, this champion colonizer soon got out of hand. The OMNRF's 2021 Garlic Mustard Fact Sheet reports "Dense stands (of garlic mustard) produce more than 60,000 seeds per square metre. Stands of garlic mustard can double in size every four years. Seeds can remain in the soil for up to 30 years and still be able to sprout. The plant can grow in a wide range of sunny and fully shaded habitats, including undisturbed forest, forest edges, riverbanks, and roadsides."

Garlic mustard is established in southern and eastern Ontario as far north as Sault Ste.Marie, in parts of Quebec, and south to North Carolina and Kentucky in the United States. Is garlic mustard in your area?

Garlic mustard is a biennial, taking two years to mature and set seed.

At left: Year two garlic mustard plant. On right: year one plant.

I describe garlic mustard as green cancer. Although the plant does not look nasty, and in its second year has pretty small white flowers, it replaces native plants through prolific seed production. Worse, its roots produce chemicals (including glucosinates, sinigrin and cyanide) that change soil chemistry, damaging microorganisms and preventing other species' roots from taking up soil nutrients. The forest ecology changes as its balance shifts (Anderson, 2012; The Nature Conservancy, 2020).

Bonus fun -not!- fact. A single garlic mustard plant can self-pollinate, meaning one plant can start a new population.

What to do?

Here’s a hint. Do not allow garlic mustard to become established. All of those flowers form seed pods FULL of tiny seeds which cover the ground around the plant.

Enough of those seeds are spread by passing animals and people to significantly impact North American forest ecosystems.

The ultimate goal in removing garlic mustard is to prevent seed development and spreading until the existing seed bank is depleted.

It's a huge problem, but we each have a role to play in solving it. Which is why, every spring, the best I can do is visit an invaded woodland. There I try to keep the number of plants from increasing:

  • First, I make sure to identify the plant as garlic mustard.

  • I try to pull up the plants before they set seed, because the action of yanking the plant from the ground will spread the seed.

  • Then, I grasp the stalk at the crown where it meets the ground and pull. My goal is to remove the entire root, knowing plants will re-grow from root scraps left in the ground.

  • Last, I put pulled plants in a garbage bag that will be taken to landfill. The flowers of pulled plants still can produce seeds, so I never compost the pulled plants.

You have the option of eating garlic mustard, high in vitamins A and C. “Harvest young, when it’s less bitter (older plants need to be cooked thoroughly as they contain cyanide). Adds spice to dips, sauces, salads, and stir fries.” (The Nature Conservancy, 2020). Cyanide? Maybe not...

I started this article by saying I was a guerrilla invasive plant puller. No more. I'm now an ex-guerrilla!

Last spring I joined my city’s Garlic Mustard Task Force. I am supplied with cotton gloves, a badge and a lanyard, plastic bags, Hazardous Waste stickers to stick to bags filled with pulled garlic mustard plants, and (not used) a tick remover.

Want to help?

It's the start of 2023. In early spring, check your local programs to find out about training and group "pulls". You can spend time in less pleasant places in spring than in a woods!

Left: Murray Moore, no longer a guerrilla garlic mustard-puller, is a now card-carrying Task Force Volunteer. Photo: Mary Ellen Moore.


Tuesday, June 2, 2020

Garlic Mustard Factsheet (2021). OFAH/OMNRF Invading Species Awareness Program

Anderson, Hayley (2012). Invasive Garlic Mustard (Alliaria petiolata) Best Management Practices in Ontario. Ontario Invasive Plant Council. Peterborough, ON.

Garlic Mustard: Invasive, Destructive, Edible (2020). The Nature Conservancy.


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