Invasive Species Spotlight: Garlic Mustard
Brought from Europe in the 1800s for culinary and medicinal purposes, Garlic mustard (Alliaria petiolata) has since become an ecological threat in North American forests and fields. Its aggressive growth and reproduction patterns allow it to outcompete natives for light, moisture, and nutrients, leading to a decline in the diversity and abundance of native plant species.
Identification
Garlic mustard characteristics vary between its two life stages. During its first year, the ground-level “basal” year, garlic mustard forms a basal rosette of kidney-shaped leaves. These leaves, which are less than four inches across, are scalloped along the edges and emit a distinct garlic smell when crushed. The rosette remains close to the ground, enabling the plant to survive winter and store energy for its next phase. In its second year, the reproductive “bolt” year, garlic mustard sends up a flowering stalk that can grow up to three feet tall. The heart-shaped leaves along the stem have toothed edges and are slightly smaller than the basal leaves. In early spring, clusters of small, white, four-petaled flowers emerge at the tips of the stems. By summer, these flowers are replaced by slender seed pods, known as siliques, which mature and eventually shatter, dispersing seeds far and wide.
Control
Managing garlic mustard requires persistence and planning, as a single plant can produce thousands of seeds, which remain viable in the soil for over five years. Hand-pulling is fortunately the most effective method, especially when done before the plant sets seed. It’s crucial to remove the entire taproot; this is best accomplished after rainfall when the soil is loose. Applying glyphosate (e.g., Roundup) during the rosette stage, particularly in late fall or early spring, can help control larger infestations. Continuous monitoring and removal is necessary to deplete the seed bank over time.
Forage It!
There’s a small silver lining to this pesky plant—garlic mustard is edible and has been used as a food source for centuries. As the name tells you, it’s a member of the mustard family and has a garlic-like kick. Young leaves are less bitter and can be used fresh in salads, pesto, and sauces. Foraging for garlic mustard can serve a dual purpose: providing a unique ingredient for your kitchen and aiding in its control throughout our ecosystems. Learn more about how to incorporate invasive plant species into your home-cooked meals in our blog about foraging for invasives.