Content and images courtesy of Wild Cohasset.
Garlic mustard is an invasive, non-native biennial herb in the mustard family, known for its strong garlic scent and ability to quickly colonize forest floors. The plant was introduced to North America from Europe in the mid 1800s for food and medicinal purposes.
It is a biennial (a 2-year plant). In the first year, it has round leaves, in its second year, it grows tall, flowers and goes to seed. Garlic mustard changes the soil chemistry where it grows, killing beneficial micronutrients and making it so that very few other plants can grow in that soil. It can spread when people dump their lawn debris and weeds onto roadsides. Free compost from most towns also often has seeds present.
Garlic mustard is a major threat to birds, butterflies and bees. It kills certain butterflies who attempt to feed on it. It also displaces the plants that wildlife need to survive, such as milkweed (monarch butterflies) and jewelweed (hummingbirds). Most local conservation areas currently have it present, including Wheelwright Park, Wompatuck State Park and World’s End Reservation. Garlic mustard seeds are found in many commercially purchased wildflower seed mixes, even though it is illegal to plant it in every state in America.
One plant this year equals up to 3,000 plants next year! Herbicides are not effective at controlling garlic mustard and harm plants and wildlife. The only way to effectively get rid of garlic mustard is to pull it.
When to Pull Garlic Mustard
Late April – Early May: pull by the roots. Throw away in sealed plastic bag with the trash. Start at the edges of infected areas and work your way in. Attack small patches before large areas.
Late May – Mid June: still okay to pull as long as you see NO black seeds on the green stems NEVER compost garlic mustard!
Early July: Once the green seed stems have turned brown OR you can see black seeds along green stems, DON’T PULL or walk through the plants. Wait until next spring or you are likely to infect new areas. Don’t walk in the woods after walking through an area with these plants!
Join Wild Cohasset for their Weeding for Wildlife event on May 10.