Most gardeners are familiar with invasive weeds, such as dandelions and nettles, which we do our best to control in the garden. But some ornamental plants have the potential to grow out of control, too, which can out-compete plants growing nearby.
You may be familiar with the worst offenders, including Japanese knotweed, Himalayan balsam and Rhododendron ponticum. These are so invasive that there there are now laws in place to limit their spread into the wild, where they can damage local ecosystems. Some of these plants, such as Japanese knotweed, are so rampant that, if you find them growing in your garden, you may have difficulty getting a mortgage (or remortgaging your home), and you will be prosecuted if you allow them to spread into a neighbour’s garden.