Invasives can be trees, shrubs, vines, perennials, annuals or aquatics and are often first planted because they are useful or attractive plants for our yards. Some native plants can also spread rapidly, but these are not usually classified as invasive.
Many invasive plants were deliberately introduced to natural habitats, for various reasons, then spread unexpectedly. Some escaped from gardens and yards, some were accidentally introduced.
It is important to remember that many plants are invasive in some parts of the country, but perfectly well-behaved in others. So each state has its own list of invasive species, your local Cooperative Extension Service or local nurseries can provide detailed information.
Controlling invasive plants is often difficult. As with how to get rid of weeds, hand pulling or digging is a widespread approach, and in some areas insects or fungi that feed on a particular invasive have been introduced. Weed killers are also sometimes used but come with their own risks. Deer can make the problem worse by eating native plants but not invasives.
For most of us the crucial thing is to make sure invasive plants aren't included in our yards and, if we see any invasives arrive, to pull them out straight away.