By Barbara Phinney
It's time to be on the lookout for the invasive biennial plant commonly known as Garlic Mustard ( Alliaria petiolata). It is a biennial evergreen growing to 3 feet in height in it's second year. Garlic mustard grows readily from seed, forming strong tap rooted seedlings that develop a basal rosette of heart shaped, toothed leaves, relatively close to the ground. The plants flower in the their second year, developing a stalk of white, four petal cross shaped flowers in early summer. Pea pod like fruits soon develop from the pollinated flowers producing 10,000 seeds per plant. Interrupting or eliminating the production and dispersal of seeds is the most effective aspect of control. These are seeds that can last from 5-7 years in the soil before sprouting. As the old saying goes: One' year's seeding. Seven year's weeding. Mowing before it blooms is another way to control the spread. After flowering and production of the seeds, the individual plant dies.
Native to Europe and parts of Asia, garlic mustard was introduced in the mid 1800's, most likely used as a potted herb. One can eat garlic mustard before it flowers. It prefers shade and is easier to pull out by hand in the Spring.
In this country, the threat from garlic mustard comes from its lack of natural enemies. Even the white-tailed deer seem to prefer native plants to garlic mustard. Because it persists through the first winter as a green rosette, it can overrun and eliminate many native plants.
Chemicals in garlic mustard have been found to affect mychorrhizal fungi associated with native trees, resulting in suppression of native tree seedling growth.