View the entire 1999 Cal-IPC List 

List A: Most Invasive Wildland Pest Plant; documented as aggressive invaders that displace natives and disrupt natural habitats. Includes two sublists:
List A-1: Widespread pests that are invasive in more than three Jepson regions.
List A-2: Regional pests invasive in three or fewer Jepson regions.

List B: Wildland Pest Plants of Lesser Invasiveness; invasive pest plants that spread less rapidly and cause a lesser degree of habitat disruption; may be widespread or regional.

Red Alert: Pest plants with potential to spread explosively; infestations currently small or localized. If found, alert Cal-IPC, County Agricultural Commissioner, or California Department of Food and Agriculture.

Need More Information: Plants for which current information does not adequately describe nature of threat to wildlands, distribution, or invasiveness. Further information is requested from knowledgeable observers.

Annual Grasses: New in this edition; a preliminary list of annual grasses, abundant and widespread in California, that pose significant threats to wildlands. Information is requested to support further definition of this category in next List edition.

Considered But Not Listed: Plants that, after review of status, do not appear to pose a significant threat to wildlands.

1999 List Review Committee

Dr. Lars W.J. Anderson, Research Leader
U.S. Dept. of Agriculture-ARS, Aquatic Weed Research Lab

Dr. Joe DiTomaso, Extension Weed Ecologist
Weed Science Program, Department of Vegetable Crops, U.C. Davis

Dr. G. Fred Hrusa, Senior Plant Systmatist
Plant Pest Diagnostics Center, CDFA

Dr. Marcel Rejmanek, Professor of Plant Ecology
Section of Evolution and Ecology, U.C. Davis

1999 Cal-IPC List Committee

Ann Howald, Instructor
Santa Rosa Junior College

Dr. John Randall, Invasive Weed Specialist
The Nature Conservancy

Jake Sigg, President
California Native Plant Society

Ellie Wagner, Botanist
California Dept. of Transportation

Peter Warner, Restoration Coordinator
Golden Gate National Parks Association