Garlic mustard (Alliaria petiolata)
Garlic mustard reproduces exclusively by seed, and it is a prolific seeder. Each mature plant can produce hundreds of seeds (average is between 130-300 seeds per plant, although plants have been found to produce as high as 7900 seeds per plant). Seeds are viable for 4 to 7 years. Although the majority of the seeds that are produced are viable, relatively few actually germinate (this is dependant by site conditions). About 40% of seedlings reach adult stage (a mature, flowering plant). Seeds are cast by mature plants in late June, July and August and lie dormant for 18-20 months. Seedlings emerge in the spring and become basal rosettes by the fall. Rosettes stay green through the winter and as a second year plant produce a flower stalk the following spring. Mature plants flower in May and set seed in late June, July or August.
Garlic mustard seeds are dispersed along trails and waterways by human activities (walking through patches, moving infested materials such as gravel or soil) and in the fur of animals such as horses, mice and deer.
Class B Noxious Weed
Photos: (c) Chris Evans River to River CWMA; (c) L. Mehrhoff University of Connecticut; (c) T. Heutte USDA Forest Service; (c) C. Black; Emily Boedecker, TNC; Daniel Dietz, TNC: