Garlic Mustard is alien and aggressively invasive, once established in an area it forms dense stands and it is nearly impossible to fully eradicate. However, with relatively little effort it can be controlled. The preferred method of plant removal is manual pulling, and in my opinion the best time of year to do that pulling is between snow melt and mid-May. After mid-May the fast growing plants have set seed and may still be pulled, but to prevent inadvertent seed dispersal they then need to be bagged in heavy black plastic and left in the sun until the plants rot and the overheated seeds are no longer viable.
It is much easier to deal with this Eurasian invader before it sets seed. Go out when the ground is rain softened, grasp a plant at ground level and pull slowly and steadily to extract the long taproot. Any unseeded plants that are pulled can be left on stonewalls, in the forks of trees or in other inhospitable dry places. But, a word of warning, any plants left in damp partially shaded places will continue to grow, flower and eventually set seed. They will turn their faces to the sun and go about the business of photosynthesis and reproduction as if still rooted in the earth.
Garlic mustard is biennial. It produces a leafy ground-level rosette the first year. The second spring a flowering stalk bolts skyward and seeds are produced. A single plant may have up to 16 seed pods each containing up to 20 seeds. Later in its second season the plant dies.
Garlic mustard’s tiny (.25 inch) white flowers are 4 petaled as are those of all mustards. Its stem leaves are triangular and deeply toothed. The rounder basal leaves are similarly toothed. Leaf veins are sunken, making the leaves appear somewhat wrinkled or quilted. The plant smells and tastes of garlic, especially when crushed.
I pull garlic mustard along 1.5 miles of gravel road near my Dummerston home,early in the season when the plants are small and have not yet produced seed. Often I pull them as rosettes. If a dry stonewall or tree fork where I can dispose of these plants is not available I sometimes throw the pulled plants onto the traveled portion of the road. Despite its reputation for being hard to kill, this invasive can’t survive being yanked from the ground and then being repeatedly crushed under automobile tires. Very little time is devoted to this invasive control project. Perhaps 5 hours a year. Seldom more than 10 or 15 minutes on any one day. Often I pull this invasive on the same days that I do roadside green-up. There are always a few garlic mustards to pull along my road. It is never eradicated, but it is well-controlled. It never dominates any area to the detriment of native species.
This is an easy invasive to identify and a relatively easy one to control. It is also edible and high in vitamins A and C and in Europe it’s harvested as a potherb. However, if you are looking for a place to harvest a batch of this odiferous invasive don’t bother looking along the roads I walk in Dummerston. Happy pulling and, perhaps, Bon Appetit !–John Anderson, Dummerston Conservation Commission