Garlic Mustard (Alliaria petiolata). As a Habitat Defender in Shenandoah National Park, this one certainly keeps me busy. Except that it is so prevalent this is an easy invasive to deal with, compared to some others.
The Invasive Plant Atlas calls Garlic Mustard an Ecological Threat. It is quite clever in its ways, being a plant that is allelopathic, meaning it produces compounds that impede seed germination of other species. It is also a plant that is quite happy to be in very dense shade, but it is equally happy growing in full sun.
Though native to Europe, Garlic Mustard first showed up in the US in 1868 and can now be found throughout the northeastern and midwestern United States.
Easy to pull, just make sure you get all the root, and if the plant is in flower, be sure to place the plant in the trash. Otherwise, those flowers will continue to mature and turn to seed, even though it has been pulled up. What a nightmare!
