The answer to 'why is my shrub invasive plants' is that your shrub may be an invasive species that is spreading and outcompeting other plants in your landscape. Invasive plants are non-native species that can grow and reproduce quickly, often crowding out native plants and disrupting the local ecosystem.
Common signs of an invasive shrub include rapid growth, prolific flowering and seed production, and the ability to spread through underground runners or self-seeding. Some examples of invasive shrubs include Japanese barberry, burning bush, and multiflora rose. If left unchecked, these plants can quickly take over your garden and become difficult to control.