Another book that we find useful in our research is "Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species" by Sylvan Ramsey Kaufman & Wallace Kaufman. It very precisely describes where the plants grow and what they look like. It provides some interesting information on where the plants originated, and when they were introduced to North America. Coincidentally, many of the plants in the book are edible. Garlic mustard (Alliaria petiolata) is in the book along with ways to eradicate it, such as pulling up the plant and poisoning the plant, but we like to eat the plant. Garlic mustard will completely overtake areas, crowding out the native plants and producing compounds that discourage growth of other plants in the area.
Garlic mustard is a biennial, meaning the plant lives 2 years then dies. The first year plants form a rosette of scalloped, kidney-shaped leaves with long stalks. The leaves emit a strong garlicky scent when crushed, and are too bitter and tough to eat. In the first year, we dig up the white taproot to use like horseradish.
The second year plants produce a long flower stalk in early spring. Several racemes of small, four-petaled, white flowers open at the top of the stalk, and these flowers will soon produce 1-3 inch long, skinny green seed pods. The pods will dry out and turn brown and papery, and the black comma-shaped seeds will fall and spread.
The flower stalk is edible before the flowers open, picked and leaves removed then lightly sautéed. The flowers are edible in salads, adding a garlicky bite. When the seeds are black and dried, they are easily separated from the papery sheaths, and we add them to toasted spice mixtures and sprinkle them onto breads. The smaller, triangular, irregularly toothed leaves growing along the flower stalk are tender enough to eat sautéed or lightly boiled. Our new favorite is gathering the green seed pods from the top, and lightly boiling them about 1 minute, then serving them with butter and salt. Other popular uses for the tender second year leaves is making a pesto, and stirring them into risotto at the end of cooking. We also add them to soups.