Herbaceous plants ("herbs") are vascular plants without significant woody tissue above or at the ground and include
flowering plants, ferns, horsetails, lycopods, and whisk-ferns. They may be annual, biennial, or perennial but always
lack significant thickening by secondary woody growth and have perennating buds borne at or below the ground surface.
Forbs are non-graminoid (grasses, sedges, rushes, etc.) herbaceous plants and represent a guild of plant species with
broadly similar growth form, which in ecology is often more important than taxonomic relationship.
The following species have been reported to be invasive in natural areas in the U.S. Species native to the U.S. are
included when they are invasive in areas well outside their known natural ranges, as a result of human activities.
For more information on each species, including the listing sources, images, and distribution maps, click on the
species.