People in urban and suburban areas often use the term “invasive” to describe plants or weeds that appear to take over a garden or landscape. However, true invasive plants are weeds that infest ecosystems, rangelands, and pasture—places common garden weeds don't thrive.
Invasive plants can reduce native plant and animal diversity, threaten endangered species habitat, and increase wildfire and flood danger. Most invasive plants were introduced as ornamentals from the retail nursery industry, or for the purposes of soil stabilization, animal forage, human food, fiber, or medicinal plants. Some may still be found for sale at retail nursery and garden centers, including the following:
Invasive plants—plants that can disperse, establish, and spread without human assistance or disturbance—pose a serious problem in California's waterways, wildlands and rangelands. Common garden weeds, unlike invasive plants, don't generally thrive outside of cultivation.
About 1,500 non-native plant species are currently established in California, mostly in wildlands. Almost two thirds were intentionally introduced as ornamentals from the nursery industry, or for the purposes of soil stabilization, animal forage, human food, fiber or medicinal plants.
Invasive plants originally introduced as desirable ornamentals include pampasgrass, big periwinkle, and water hyacinth. Dyer's woad was once a valuable dye...