Skip navigation

PlantRight

Impacts

Impacts of Invasive Plants

Broom invading a hillside by the highway. Disturbed areas are prone to plant invasions.Broom invading a hillside by the highway. Disturbed areas are prone to plant invasions.

Most of the plants used in gardens and landscaping do not invade or harm wildland areas. But a few vigorous species can — and do — escape into open landscapes and cause a variety of ecological problems. They displace native plants and wildlife, increase wildfire and flood danger, clog valuable waterways, degrade recreational opportunities, and destroy productive range and timber lands.

When an aggressive plant is introduced to a new environment, the predators that would normally limit their growth in their home environment may not be present. This allows them to proliferate, spread, and take over natural habitats.

Periwinkle plants shown invading ecologically and economically valuable land in coastal CaliforniaPeriwinkle plants shown invading ecologically and economically valuable land in coastal California.

Invasive species are one of the greatest threats to biodiversity worldwide, second only to habitat destruction. And the economic cost is as significant as the ecological cost: in California, more than $82 million goes to fighting invasive plants every year. A much-cited paper by Cornell researchers estimates the economic impacts of invasive species to be $120 billion a year. If divided equally through the 50 states, the cost to each state averages $2.4 billion annually — and given California's size and resources, the actual impact is likely greater.

It is widely agreed that prevention is the most effective and resource-efficient way to combat the spread of invasive plants. Please visit our pages for home gardeners and for nursery professionals to learn more about how you can prevent the spread of invasive garden plants.