Athens County Invasive Exotics Control Program
Garlic mustard, Alliaria petiolaria

  
All images on this page are courtesy of the US Forestry Service, USDA		 
Garlic mustard is a biennial, meaning that it grows its first year as a low rosette of leaves, then in its second year sends up a flowering spike, sets seed and dies. The seeds are small and the plant spreads mostly by seed drop. Seeds are also sometimes washed downstream or hitchhike in mud stuck to shoes, animal paws, bicycle tires or car tires. This plant forms dense colonies over woodland areas, positively shading out and crowding out native wildflowers and ferns. It also produces a fungicide that spreads in the soil around it to kill mycorrhizal fungi, inhibiting the growth of other plants around it, even large trees. While the second-year plants die out around midsummer, it is evergreen between its first and second years.

Eradication tips:

Pull in early to mid-April, and then again in mid-May, and pull second-year plants first, which are starting to form a flowering spike. If it's pulled before seed pods are set, then it may be composted, or hung over branches to dry out or left on a roadway or trail surface. However, if the seed pods are already set, then the plant should be bagged for the landfill or burned. When pulling, grasp the plant as far down as possible, preferable at the top of the roots, since they have a tendency to break off just above the roots and then the roots grow a new plant. It's important to pull again in mid- to late May, because small plants often send up flowering stalks later than the larger plants. It may also be pulled at any time during the winter, when it's easy to spot when there's no snow on the ground, because it is very brightly evergreen.