In California, exotic plants were originally introduced by humans who planned to use them for ornamental or aquarium use, or for use as forage, food, fiber, medicinal or soil stabilization purposes. In some cases, the unintended outcome has been plants that have become invasive.
Some invasive plants are still for sale at retail nursery and garden centers. Some examples of available invasive plant species include pampasgrass (Cortaderia selloana), Scotch broom (Cytisus scoparius), English ivy (Hedera helix) and crimson fountaingrass (Pennisetumsetaceum), and Mexican feathergrass (Stipa tenuissima).
Most gardeners and landscapers unknowingly purchase invasive plants. When buying plants, they look for those that are attractive and do well in the landscape; and some invasive plants fit these criteria. However, there are many alternatives to invasive plants that look similar, but don't pose a risk to California's environment and economy.
If you want to avoid purchasing invasive plants, read the Pest Note: Invasive Plants for help with identifying invasives. You can also visit the PlantRight website and look for Plants by Region of California for recommendations on which plants to purchase instead.