Bridge Gardens’ Weed of the Month | Garlic mustard (Alliaria petiolata)

Garlic mustard is native to Eurasia and was introduced to North America by European settlers for culinary and medicinal purposes in the 1800’s. It was recorded growing on Long Island in 1868. One of the oldest spices of the Old World, its use by ancient peoples has been well-documented. All parts of the plant have a garlicky, mustard-y aroma and flavor and have been used in sauces, salads and pestos for millennia. The whole plant has also been used medicinally as a diuretic.

A member of the mustard family, garlic mustard is a biennial. During its first year of growth is forms a rosette of triangular or heart-shaped, wrinkly leaves. Plants bloom in the spring of the second year on elongating, spikey stalks that can reach 12-18 inches tall and more. Flowers are small and appear in clusters, appearing in late April and continuing throughout spring. White and four-petalled, they mature into capsules full of small, shiny black seeds that disperse far and wide.

Considered an invasive species throughout North America, garlic mustard is found in forests, meadows, gardens and roadsides. It grows best in shade but is also sun tolerant. Sites invaded by garlic mustard have shown a decline of native woodland species, both herbaceous and woody, and research has shown that chemicals released into the soil by the plants have a negative effect on soil fungi and the growth of native plants.

Hand-pulling is the best control and best in spring and early summer before seeds form. This can be time-consuming and tricky, considering the plant’s deep taproot. Cutting the plant at the base before flowering is also effective but may need to be done repeatedly.