What is Garlic Mustard?
Garlic mustard (Alliaria petiolata) is an invasive plant native to Europe and parts of Asia. Today, it is commonly found in woodlands, roadsides, and disturbed habitats, where it often displaces native plants due to its aggressive growth and rapid spread.
Key Characteristics
- Appearance: Garlic mustard is a biennial plant, meaning it has a two-year life cycle. In its first year, it forms rosettes of rounded, green leaves close to the ground. In its second year, the plant grows tall (up to 4 feet), producing clusters of small, white flowers.
- Leaves: The leaves of garlic mustard have a distinct heart-like shape and are coarsely toothed. They emit a garlic-like odor when crushed, which is where the plant gets its name.
- Flowers: The small white flowers bloom in late spring (April to June) and are arranged in clusters at the top of the plant. Each flower has four petals.
- Seed pods: After flowering, garlic mustard produces seed pods called siliques that are slender, elongated, and typically 2-3 inches long. They are green when immature and turn brown or dark in color as they mature. The pods contain seeds, and when fully mature, they split open along one side, releasing the seeds into the surrounding area.
- Seeds: One garlic mustard plant can produce up to 8,000 small, dark seeds that are spread primarily by gravity, but can also be moved by animals or human activity. The seeds remain viable for several years, making it difficult to control the spread of the plant.
How Did Garlic Mustard Get Here?
It was introduced to North America in the 1860s for culinary and medicinal purposes. The young leaves of garlic mustard have a strong garlic flavor and can be used in salads, pesto, or as a garnish. They can also be cooked like spinach, though the flavor is more pungent. Historically, garlic mustard was used in herbal medicine to treat various ailments, such as colds, coughs, and digestive issues.
The plant’s ability to grow in a wide range of environments, including woodlands, roadsides, and disturbed areas, made it adaptable to a variety of regions, including the Midwest. In the case of Eden Prairie, as in many other areas, garlic mustard likely arrived through a combination of human activity and natural spread:
- Agricultural or Horticultural Practices: The plant could have been introduced accidentally through the movement of soil, mulch, or plant material, often during landscaping, road construction, or development of new areas. This is common with invasive species, as their seeds or root fragments can hitch a ride on equipment or in materials used in these activities.
- Wildlife and Human Activity: Birds, animals, or even people could have played a role in spreading garlic mustard seeds. The plant’s small seeds can travel great distances, often being carried on footwear, clothing, or vehicle tires.
Once garlic mustard was introduced, it likely spread rapidly in Eden Prairie due to its ability to thrive in disturbed habitats like small woodlands, parks, and even roadsides, which are common in suburban areas like Eden Prairie. Garlic mustard was listed as a Restricted Noxious Weed by the Minnesota Department of Agriculture in 2013.
Why Is Garlic Mustard a Problem?
Garlic mustard is considered a highly invasive species. It grows rapidly and out-competes native vegetation, reducing biodiversity and disrupting local ecosystems. When native plants are pushed out, pollinators and other local wildlife lose essential food and habitat sources. Some of the key reasons for its invasiveness include:
Fast Growth
The plant grows quickly and spreads aggressively—often crowding out native wildflowers and ferns. In fact, a single garlic mustard plant can produce up to 8,000 seeds, which means it can take over large areas of woodland in just a couple of seasons.
Allelopathy
This invader isn’t just stealing space and sunshine. Garlic mustard releases chemicals into the soil that disrupt beneficial fungi and harm many native plants by preventing germination and root development, a condition called allelopathy. A healthy ecosystem depends on thriving native species, so garlic mustard’s takeover can throw everything out of balance
Lack of Natural Predators
In its native range, garlic mustard has natural predators that keep its population in check. However, in North America, it lacks these natural controls, allowing it to proliferate uncontrollably.
Earthworms
Some studies suggest that the presence of earthworms can facilitate the spread of garlic mustard. Since earthworms will eat the roots of native plants, bare areas of the forest floor are created and there are openings for garlic mustard to take hold and spread
White-tailed Deer
White-tailed deer strongly dislike eating garlic mustard and prefer native vegetation. In areas with high deer densities like Eden Prairie, the deer can significantly reduce the cover of native vegetation, making more space for garlic mustard to spread.
How Do We Get Rid of Garlic Mustard?
Identify a Target Area with Garlic Mustard
- The first step in removing garlic mustard from a park is to identify a target area that we want to restore.
- Friends of Eden Prairie Parks works closely with the city of Eden Prairie to determine priority areas for garlic mustard removal.
- It is important to protect high-quality areas and prevent garlic mustard from taking over and outcompeting the native vegetation.
Remove Garlic Mustard
- Pulling up the plants, including the roots, is one of the most effective ways to prevent garlic mustard from reseeding. This should be done before the plant goes to seed in late spring or early summer.
Follow Up Management
- Maintaining management in an area for up to ten years is essential, because when plants are pulled the soil is disturbed which can promote growth of garlic mustard seeds in the seed bank.
- You must go back to the area and pull garlic mustard plants every year until there are no more viable seeds in the seed bank.
- If you do not continue to manage the site, the infestation will only worsen.
Sustain our Success
- Friends of Eden Prairie Parks works with the city of Eden Prairie to strategically target garlic mustard sites and ensure the site will be managed for at least 10 years, ensuring the protection of Eden Prairies native plants and ecosystems for years to come.
How Can I Help?
Simple to Remove—No Herbicides Needed
The good news? Garlic mustard is relatively easy to pull by hand, especially in moist spring soil. A pair of gloves, a bag to collect the plants, and a sharp eye are all you need to make a huge difference. No special skills required!
You Can Help Protect Eden Prairie’s Future
Volunteering just a few hours to remove garlic mustard ensures our natural spaces remain diverse, beautiful, and welcoming for generations to come. By stepping in now, you’ll be a part of restoring habitats that support local wildlife—and help keep our community green and vibrant.
Ready to Take Action?
Join Friends of Eden Prairie Parks this spring at one of our scheduled removal events. Your hands-on help matters—together, we can stand up to this invasive plant and protect the native splendor of our community’s natural spaces. Visit our Events Page and mark your calendar today!