In different regions of the United States, some examples of invasive plant species include Russian olive, kudzu, Japanese honeysuckle, leafy spurge, purple star thistle, diffuse knapweed, garlic mustard and witchweed, notes InvasiveSpeciesInfo.gov. An invasive plant species is one that can grow and spread quickly outside its natural habitat and can cause harm to native plants when introduced into a new habitat.
When introduced into a new ecological environment, an invasive plant species, which is typically a non-native plant, can also have adverse effects on humans or the economy of a region, notes Fed.us. When invasive plants aggressively spread in a region, it can also lead to some native plant species becoming endangered.
Some other invasive plant species include purple loosestrife, tamarisk and witchweed. As of 2015, tamarisk and Russian olive are causing problems in the western region of the United States, notes USDA.gov. Gardeners are advised not to plant purple loosestrife because the plant seeds can easily be dispersed by waterfowl or wash up along streambeds and establish in a new region. Removal of this plant should be attempted only if it is a young plant.
Tamarisk, which has the botanical name of Tamarix ramosissima, is a deciduous shrub found in areas that include parts of California and Arizona. Witchweed is an example of a noxious weed. This plant is native to Africa and Asia, but has established itself in North Carolina and South Carolina. This invasive plant is found on the Federal Noxious Weed list.