What do you call any plant that is growing where it is not wanted?

A plant that is growing where it is not wanted is termed a weed. Weeds are typically characterized by their vigorous growth and ability to thrive in conditions where they compete with desired plants, such as cultivated crops or ornamental gardens. They often disrupt the ecosystem, interfere with crop production, and may harbor pests or diseases that can affect other plants.

In contrast, the other terms refer to specific categories of plants. An invasive species usually refers to a non-native plant that spreads uncontrollably and can cause ecological harm, but not all weeds are invasive. Native plants are those that naturally occur in a specific region, whereas flowering plants are any plants that produce flowers, which may or may not be considered weeds depending on the context in which they are growing. Thus, the term that best describes any plant growing unwanted is indeed a weed.