Ecological Threat in the United States
Garlic mustard has displaced vast areas occupied by native spring wildflowers like spring beauty (Claytonia virginica), wild ginger (Asarum canadense), bloodroot (Sanguinaria canadensis), trilliums (Trillium species) and toothworts (Cardamine). Three native butterfly species, the West Virginia white (Pieris virginiensis), mustard white butterfly (Pieris oleracea), and the falcate orange-tip (Anthocharis midea annicka), are especially impacted when garlic mustard displaces toothworts, its host plants. Chemicals in garlic mustard are toxic to the larvae of the native butterflies. Other chemicals have been found to affect mychorrhizal fungi associated with native trees, resulting in suppression of native tree seedling growth.