Welcome to the “Weed Web site” at Penn State University. As you know, weeds can be native or alien invasive plants that harm agricultural, disturbed, and natural ecosystems. Some people call weeds “plants out of place”, but to farmers, conservationists, land managers, and even homeowners, weeds can be extremely problematic. We hope you will visit our “Weed Web site” often to learn about Penn State weed management research and education programs and to also link to other sites that can help you manage these problem plants. We welcome your comments and suggestions.