Gardeners have been warned to keep an eye out for 'illegal' invasive plants, common and annoying species not native to the local area. These unwanted garden guests play havoc with local ecosystems and can even damage the structural foundations of homes.
Invasive plants are defined as any plant which grows where gardeners don't want it to, and are usually difficult to control. The most famous is Japenese Knotweed, which spreads wherever it can root, grows incredibly quickly, and is very difficult to remove.
Some of these plant-based invaders are imported, which can mess with the local environment and food chain, edging out local plants and threatening native species. National Geographic describes invasive species as: "an organism that is not indigenous, or native, to a particular area."
