Garlic mustard (Alliaria petiolata) is a biennial forb that originated in Europe. Early settlers brought garlic mustard to North America as an edible and medicinal herb. It was first reported in Long Island in 1868 and is most abundant in the Northeast and the Midwest.
During its first year, garlic mustard grows as a rosette — a circular arrangements of leaves — close to the ground. It has green scalloped, kidney-shaped leaves. Mature plants reach 2 to 3.5 feet tall and have clusters of small white flowers. Each flower has four petals in the shape of a cross. Garlic mustard seeds develop in erect, slender, four-sided pods beginning in May and are viable for up to 20 years.
Garlic mustard is found in disturbed shaded areas, woodlands and floodplains. The plant is “allelopathic,” which means it releases chemicals that suppress native plants, especially spring wildflowers. Animals that depend on early native wildflowers for foliage, pollen, nectar, fruits, seeds and roots are deprived of these essential sources of food when garlic mustard replaces them.
To successfully control garlic mustard, gardeners must prevent plants from dropping their seeds for several years until all viable seeds are exhausted. After the plants flower but before they set their seeds, gardeners should pull the plants or cut their stems at ground level and then remove the plants from the site.
Click here to watch a video on the damage garlic mustard causes in woodlands and how you can help with efforts to curb the spread.